Prague Castle, Czech Republic

The largest ancient castle complex in the world at 70,000 square metres, Prague Castle has dominated the Czech capital since its founding in the 9th century and serves today as the official residence of the Czech president. The complex encompasses St Vitus Cathedral (begun 1344), the Old Royal Palace, the Basilica of St George, and Golden Lane. UNESCO listed it as a World Heritage Site in 1992 and it receives over 3 million visitors annually.