Fireworks lit the sky, Zagreb's medieval cannon fired and a choir sang Beethoven's Ode to Joy as Croatia became the 28th member of the European Union at midnight on Sunday (June 30), two decades since fighting itself free of Yugoslavia.
Two men clad in white abseiled from a nearby building to bring the EU's yellow-starred blue flag to the central Ban Jelacic square, packed with around 20,000 cheering Croatians.
The ceremony represents a milestone in Croatia's recovery from a 1991-95 war to secure independence in which some 20,000 people died, but was held against a backdrop of economic woes in the Adriatic republic and the bloc it is joining.
The country's Adriatic coastline has since become a magnet for some 10 million tourists every year, but a biting recession now in its fifth year has taken the shine off Sunday's celebration.
The country of 4.4 million people becomes only the second of the seven states carved from federal Yugoslavia to enter the EU, following Slovenia in 2004.
Croatia's accession marks the first expansion of the EU eastwards since 2007, when Romania and Bulgaria joined, and the "Big Bang" enlargement of 2004 when 10 new members came aboard.
Croatians voted in favour of joining the EU in a 2012 referendum, but the bloc's crippling debt crisis and rising youth unemployment have many questioning the wisdom of accession.
To join, Croatia has gone through seven years of tortuous and often unpopular EU-guided reform.
Presented by Adam Justice