The Schengen Agreement established a passport-free travel zone across most of Europe. It began in 1985 with five countries agreeing to abolish border checks. By 1995, several other countries had joined and fully implemented the Schengen rules, allowing passport-free travel for EU citizens. The Schengen Area now includes 26 European countries and aims to balance open borders with security by sharing law enforcement data and coordinating police activities across members.