Croatia joined the European Union at midnight on Sunday with the EU's anthem "Ode to Joy" performed in Zagreb's main square.
There was also a fireworks display and a 3D mapping of great Croatian inventions and discoveries.
Among those who addressed the thousands in attendance was scientist Ivan Djikic.
Also performed was Croatian composer Jakov Gotovac's "Ode to Freedom".
Shortly before midnight, rock climbers of the Matica Mountaineering Club descended from the roof of Dubrovnik hotel with the EU flag.
Open air celebrations of Croatia's EU accession were held in all major towns throughout the country.
