Faced with a sea of party acronyms and percentages, even the most ardent of Europhiles is likely to struggle to decipher what's going on.
But fear not, here is our guide on what to look out for as results begin to come in for the EU elections on Sunday evening.
At the European level, look out for the performance of the European People's Party (EPP) and Socialist & Democrats (S&D) groupings.
This centre-right, centre-left axis has dominated the European Parliament for years.
But they are under threat from right-wing, anti-EU populists, including France's National Rally, Italy's League party, Germany's AfD and the Finns Party.
The other trend to look out for is whether the climate change protests will spark success for green movements.
Also, what about turnout? It's been falling at every election since the first one in 1979. If it's anything lower than 42.61% that trend will continue.
READ MORE: Video: European elections — if turnout is down, who is voting?
The big question in Austria is what impact the so-called Ibiza scandal will have on the far-right Freedom Party (FPO).
Its leader, Heinz-Christian Strache, resigned as Austria’s vice chancellor earlier this month after a secret video appeared to show him trying to trade public contracts for party donations from a woman he thought was the niece of a Russian oligarch.
Austria scandal: What we know about the video which brought down the government
FPO came third in 2014's EU elections with 19% of the vote; latest projections suggest it will pick up around 18% this time, but that figure is down from 24.5% before the scandal broke.
Belgium isn’t holding just one election on Sunday, but three: federal, regional and European.
In the latter, will the greens capitalise on a strong showing in local elections to improve on their 6.6% vote share in 2014?
Like many other European countries, Belgium also has a far-right party, Vlaams Belang, which is forecast to get up to 14.8% of the vote in Flanders.
Nationally, the party got 4.2% five years ago.
Even though voting is compulsory in Bulgaria, in 2014 voter turnout was only 35.84 %
Bulgaria's vote is expected to be split between the centre-right GERB party and the country's socialist coalition party.
The youngest current European parliament member is Bulgarian Andrey Novakov, who is 30.
The second youngest member state of the European Union holds its vote on Sunday. Turnout is expected to be low. In 2014, it was far below the EU voter turnout average at just over 25%.
Though the mainstream Croatian Democratic Union (HDZ) is a clear frontrunner, as it was in 2014, many smaller parties are in play this election due to discontent with the mainstream parties.
Croatia is one of six EU countries that is not yet a member of the Schengen Area.
The island country south of Turkey has 6 seats in the EU parliament and could make history as a Turkish Cypriot candidate is poised to be elected MEP for the first time, according to AFP.
Cyprus is a divided country between Greek Cypriots and minority Turkish Cypriots, but over 80,000 Turkish Cypriots are reportedly eligible to vote in EU elections. There is a UN buffer zone that splits the country between the internationally recognised state in the South and the de facto state in the north.
Cypriot President Nicos Anastasiades encouraged citizens to vote in the election on Sunday, according to national Cypriot media reports.
The Czech Republic voted Friday and Saturday as part of a two-day voting process in the EU elections.
Most of the votes are expected to go to the ruling ANO party which has MEPs in the Alliance of Liberals and Democrats for Europe (ALDE). The anti-establishment, anti-corruption Czech Pirate party is also expected to capture seats after an unprecedented rise in popularity over the past few years.
The Czech Republic has several new parties this year as well and its anti-EU Freedom and Direct Democracy party is expected to win its first seats in parliament.
There are fears the dramatic campaign for Denmark’s general election — set for June 5 — will overshadow the European Parliament poll and hit turnout.
Some are saying Danes are more concerned with the domestic vote, which is predicted to see Stram Kurs, a far-right party advocating the forced deportation of up to 700,000 Muslims, gain seats in parliament.
Voter turnout for EU elections in Denmark was 56.32% in 2014, 59.54% five years earlier and 47.89% in 2004.
The key question in Estonia is whether anti-EU, far-right party Eesti Konservatiivne Rahvaerakond (EKRE) will perform as well in these European elections as it did in March’s national poll.
That election saw EKRE come third, winning it a place in the ruling coalition.
The party won 4% of the vote in 2014’s European poll; this time around it is forecast to get as much as 17%.
Finland is another country that is predicted to see a green surge.
Forecasts suggest the country’s environmentalist movement is set to get the second biggest share of the vote.
Its predicted 17.2% vote share would be more than double its performance in 2014.
All eyes will be on whether the party of pro-European president Emmanuel Macron — under pressure domestically from the anti-government “gilets jaunes” (yellow vests) protesters — will be beaten into second place by Marine Le Pen.
Le Pen — who lost out to Macron in France’s presidential election — and her National Rally movement is forecast to get the biggest vote share in Sunday’s election.
Her previous party, Front National, won the 2014 vote with a 24% share. Macron’s La Republique En Marche! movement did not exist then.
There has been a surge in support for the German Green Party in federal polls and some are even daring to dream the movement could spawn its first chancellor.
In forecasts for the European Parliament elections, it has been polling in second at around 18%, which is an improvement on its 10.70% vote share in 2014.
It is worth keeping an eye on the anti-migrant and anti-euro Alternative for Germany (AfD), who won seven seats five years ago and entered the national parliament for the first time in 2017.
With national elections due in October, Greeks have been concentrating on domestic issues ahead of the EU poll.
The country’s economic situation and the name change agreement with North Macedonia have taken precedence over European issues.
The ruling Syriza party is trailing the conservative New Democracy movement in opinion polls ahead of the vote.
Some have speculated that any win for Prime Minister Alexis Tsipras and his Syriza party would prompt him to call a snap general election in June.
Hungary’s nationalist prime minister Viktor Orban has frequently clashed with Brussels over rule of law and migration.
The conflict has seen his Fidesz party suspended from the centre-right European People’s Party grouping in the parliament.
It will, therefore, be interesting to see whether this hostility affects Hungarian voters.
In 2014 right-wing anti-EU parties came first and second: Fidesz with a 51.48% vote share and Jobbik on 14.67%.
Will it be different this time around?
Ireland went to the ballot box on Friday and the Pro-EU Fine Gael party of Prime Minister Leo Varadkar was expected to be the biggest party.
Meanwhile, the Green party had a strong showing and is likely to become the fourth largest party in Ireland.
The future of the Italian government is strictly connected to the outcome of the European Parliament elections.
The two ruling parties, The League and the Five Star Movement, have spent the last couple of weeks fighting about every topic on the political agenda.
Polls predict Deputy Prime Minister Matteo Salvini's party will come out stronger than ever. His party, then the Northern League, won 6% of the vote in 2014. Latest projections suggest the League will get more than 30% this time around.
If he is crowned winner, will he pull the plug and call for new elections, with the aim of forming a right-wing led government and dismiss the despised ally?
Latvians headed to the polls on Saturday to vote for the 8 seats they have in the European parliament.
New Unity — the party aligned with the EPP — is expected to come in first, according to Latvia national media LETA . The right-wing National Alliance party is one to watch as results are confirmed from Saturday's vote.
Turnout in the 2019 elections was 33.03%, close to the 30.24% voter turnout in 2014. Lithuania
While voting to fill 11 seats in the European Parliament, Lithuania is also holding the second round of its presidential election.
Centre-right rivals Gitanas Nausėda and Ingrida Šimonytė will face off Sunday in the runoff as neither candidate received a majority during the first round of voting on May 12. Luxembourg
Luxembourg will vote for 6 MEPs for the European Parliament one of the smallest representative groups in the EU.
Voting is mandatory in the country of just over half a million people. In 2014 voter turnout was 85.55%.
There is no far-right Eurosceptic party in Luxembourg that advocates for the country's exit from the EU.
Government corruption will be a large topic in Malta during the EU elections as the two major parties have both accused the other of corruption.
Still, mainstream parties are expected to top the election. Even though Malta has two far-right Eurosceptic parties, it's unlikely that they will gain seats in the European Parliament. Poland
Poland’s EU elections kick-off a series of polls in the country: a parliamentary one follows in the autumn before a presidential vote next year.
Some say polls point to this being the beginning of the end for the ruling Eurosceptic Law and Justice Party (PiS).
With the country at odds with Brussels over the independence of its judiciary, it will be interesting to see if PiS can improve on its 31.78% vote share in 2014.
All eyes will also be on Poland’s first openly gay politician Robert Biedroń and the performance of his newly-formed pro-EU party Wiosna (Spring).
Portugal is one of the few EU countries without a strongly-performing far-right populist party.
This election has seen the emergence of Andre Ventura’s radical-right Basta! (Enough!) movement, which opposes the EU.
Campaigning has focussed on the opposition attacking Portugal’s ruling socialists on domestic issues, with an eye on a forthcoming national poll.
It will, therefore, be interesting to see whether the pro-EU socialists are able to better their performance from 2014 when they got 34% of the vote.
The ruling Social Democrats (PSD) have clashed with Brussels over anti-corruption and rule of law reforms.
It will be interesting to see if they manage to come out on top, amid conflict with the EU and regular anti-government protests.
Running them close will be pro-EU National Liberal Party (PNL). Both parties are predicted to get around 28% of the votes.
PNL and other pro-EU parties may be helped by the fact there is a referendum being held at the same time on PSD's controversial reforms .
One of the most interesting things to watch in Slovakia is turnout: just 13.05% voted in 2014, the lowest figure in the EU.
Look too at the performance of Progressive Slovakia, the party of newly-elected pro-EU president Zuzana Caputova, and compare it with the anti-Brussels, far-right movement of People's Party - Our Slovakia.
Read more: How EU elections have seen far-right rise in Slovakian politics
Meanwhile, while the ruling social democrats (SMER-SD) are predicted to win, their vote share could fall — from 24% in 2014 — after anti-government protests over the last year.
Slovenia has traditionally had low voter turnout in EU elections.
The country has several left-leaning mainstream parties but many will be watching how the EPP-aligned Slovenian Democratic Party fares as the right-wing party has recently become more populist. Spain
One curiosity of Spain’s EU poll is whether ex-Catalan leader Carles Puigdemont — currently exiled in Belgium — will get elected.
And, if he does, whether he’ll be able to take up his seat, as Euronews looked at in this article.
READ MORE: Independence puzzle for European Parliament
More widely, will the far-right Vox Party be successful in getting its candidates to Brussels and Strasbourg?
Or will it be a repeat of April’s general election? That poll saw an important Socialist majority and a lower-than-expected result for Vox.
Will Swedish teenager Greta Thunberg’s climate campaigning across Europe help persuade her compatriots to back environmentally-conscious parties?
Sweden’s Greens came second five years ago, with 15.41% of the vote, but may feel they can improve on that this time.
Experts also say to look out for the performance of the far-right Sweden Democrats, who have softened their stance on Europe in the light of Brexit. They got two MEPs for their 9.67% vote share last time around.
Anti-EU parties, including Geert Wilders' Freedom Party (PVV), were forecast to pick up more than one-third of the vote share.
Will voters punish the traditional two main parties — Labour and Conservative — for failing to deliver Brexit by switching to the new political movement fronted by anti-EU MEP Nigel Farage?
And while the anti-Brexit vote will be split by the Liberal Democrats, the Green Party and Change UK, will it add up to more than that of Farage’s Brexit Party?
Article contributors: Thomas Siemienski; Rafa Cereceda; Rita Palfi; Patrik Ohberg; Pantelis Petrakis; Lillo Montalto Monella; Lauren Chadwick; and Carolin Küter.