Prague Castle was founded around 870 - 880 by Prince Bořivoj. It is the largest castle complex in the world.

The first settlement was established at the site of current Prague in the 8th century, in Lesser Town (Malá strana). Prague, the capital of the Czech Republic, was founded along with Prague Castle around 880.

At 270 miles the Vltava River is the longest river in the Czech Republic. It starts at the Bohemian Forest and flows into Elbe (Labe) at Mělník north of Prague.

References: Prague Castle - Prague Castle (Pražský hrad) - Vltava River - History of Prague through the Centuries - History Of Prague