Prague's historical core - some parts of which date back to the 14th Century - is on the Unesco World Heritage list.
Known as the "golden city of 100 spires" and a "symphony in stone", Prague boasts architectural styles ranging from the Renaissance and Baroque right up to the art nouveau and cubist styles of the 20th Century.
Under communism the city was one of Europe's best-kept secrets, more renowned in the West for the images of Czech civilians standing up to Soviet tanks as the 1968 Prague Spring came to an end.
But since the 1989 Velvet Revolution, it has emerged as one of Europe's prime tourist destinations.
Flawed defences
Prague's authorities say they are prepared for a flood on the scale of the city's last major deluge in 1890, which inflicted major damage on low-lying areas of the city.
Experts say a major flood occurs roughly every 100 years, so this latest one is more or less on time.
The embankments of the Vltava river were designed after the 19th Century flood, but are thought to have crucial gaps.
City officials seem particularly concerned about the fate of the Baroque palaces and gardens of the Mala Strana, or lesser town, nestling on low ground between the Vltava river and the castle above.
The area is connected to the eastern side of the city by the historic 15th Century Charles Bridge.
The bridge - which boasts statues of saints every 10 feet along its entire length - is a prime tourist attraction, normally filled with buskers and street artists.
But it is vulnerable in times of flood - in the past debris carried downstream on the floodwaters has knocked out some of its arches.
Other historic areas possibly under threat include:
Fortunately, two historic fortresses - Hradcany containing the Czech president's castle, and Vysehrad in the south of the city - are both safe from the flood waters.