One of the largest squares in the world, Charles Square is lined with a number of exquisite historical buildings of various styles - from Baroque to neo-Renaissance. Although it is now named after its founder, Charles IV, the square was originally called the Cattle Market.
Adjacent to the square, there is a metro station on Line B, Karlovo náměstí. It is also a major tram hub.
Wikipedia https://en.wikipedia.org/wiki/Charles_Square
More information http://www.prague.eu/en/object/places/201/charles-square-karlovo-namesti?back=1
Address Karlovo náměstí, Praha 2 - Nové Město, 120 00, Czech Republic
Coordinates 50°4'35.962" N 14°25'12.594" E