A playground is a piece of land, at school or in a public area, where children can play.
N-COUNT
（某一群體的）游憩勝地，度假場所
If you describe a place as a playground for a certain group of people, you mean that those people like to enjoy themselves there or go on holiday there.
例句
...St Tropez, playground of the rich and famous.圣特羅佩，富豪和名流的游憩勝地