As Hungary and eight other EU countries join the Schengen zone, Hungarian PM Ferenc Gyurcsany (C) and his ministers hold a dismantled barrier at the border town of Hegyeshalom.
Fireworks, music and cheers across the nine newcomer nations greeted the expansion of the border-free zone - which now embraces 400m people.
These Polish officials held their own celebrations as the EU extended the area for passport-free travel to include eight former communist countries in Eastern Europe, plus Malta.
In places like the Hungary-Slovakia border, separated by the Danube, people walked freely across the river bridge as fireworks lit up the night.
Friday morning saw official celebrations in many places, such as Zittau, where the borders of Germany, the Czech Republic and Poland meet.
In Frankfurt/Oder, on the German-Polish "frontier", border guards from each country have begun joint, bilingual patrols.
Border controls in a long arc from Estonia to Malta are redundant for the 24 countries now belonging to the Schengen area.
These Estonian border guards were on duty as passport checks were being eliminated at land and sea ports. Airports will follow at the end of March 2008.
Poland's frontier with Ukraine is now at the eastern limit of the border-free Schengen zone.