hotbed
noun uk/ˈhɒt.bed/ us/ˈhɑːt.bed/
a hotbed of something （不良行为活动的）温床
a place or situation where a lot of a particular activity, especially an unwanted or unpleasant activity, is happening or might happen
The police department was a hotbed of corruption. 警察部门曾是腐败的温床。
In the 60s the city was a hotbed of crime. 20世纪60年代，这个城市是一个犯罪的温床。