A timeline of how Europe has gradually legalised gay marriage.
Austria is the latest European country to legalise same-sex marriage.
It joins a more than a dozen European Union states – and 16 across Europe – to allow gay people to tie the knot.
Here we take a look at how Europe has turned pink since the Dutch allow the practice at the start of the 21st century.
2001: The Netherlands becomes the first country in the world to legalise same-sex marriage in April of this year.
2003: Neighbours Belgium follow suit.
2005: Spanish MPs vote to approve gay marriage in June, despite strong opposition from the Roman Catholic Church.
2009: Norway becomes the first Nordic country to allow same-sex civil marriages in January. Church weddings were approved in 2016. Later in 2009, Sweden lets homosexuals marry in civil or religious ceremonies.
2010: Iceland, the first country in the world to have an openly gay head of state, approves same-sex marriage in June.
2012: Denmark, the first country in the world to recognise civil partnerships for same-sex couples in 1989, approves gay marriage 23 years later.
Mapped: how Europe has turned pink since 2001
2013: Gay marriage is approved in France, sparking a large protest movement.
2014: Gay marriage becomes legal in the United Kingdom, apart from Northern Ireland.
2015: Same-sex marriage becomes legal at the turn of the year in Luxembourg. Ireland then becomes the first country to approve gay marriage by popular vote.
2017: Finland votes to allow same-sex marriages, before Germany becomes the 14th country in Europe to approve same-sex marriage.
Malta and then Austria become the next countries in 2017 to approve same-sex marriage, but it won’t be lawful in the latter until 2019.