Lovely Letná Gardens (Letenské Sady) trace a rocky bluff above the Vltava on the opposite side of the river from Staré Město (Old Town). The views from up here are, well, sublime. The park is popular as a place to walk, jog, rollerblade and bike. Toward the western end of the gardens, a giant, creaking Metronome stands atop a high hill. This marks the spot where an imposing 15m statue of Soviet leader Josef Stalin stood from 1955 until 1962. In summer, an open-air music club, appropriately called "Stalin," draws crowds to hang out on the steps and listen to (often) electronic music.
From the Old Town, find the entrance up a steep staircase at the northern end of Pařížská ulice (across the bridge). Alternatively, take the tram to Letenské náměstí and walk south for about 10 minutes.