Situated under the Legion Bridge, this island's name refers to a 15th-century tradition of holding shooting competitions here. The name has been changed many times, including for instance the Lawn or Little Venezia. It is now a popular city park with a restaurant offering great views of the riverside. The area ocasionally serves as a concert and event venue.
Wikipedia https://en.wikipedia.org/wiki/Střelecký_Island
More information http://www.prague.eu/en/object/places/518/shooter-s-island-strelecky-ostrov?back=1
Coordinates 50°4'52.283" N 14°24'36.254" E