sister city

1. N-COUNT Sister cities are cities in different countries that have formally established a special relationship with each other involving, for example, cultural and sports events. 姊妹城市; 友好城市[美国英语]

...dancers from Palo Alto's Mexican sister city, Oaxaca. ...从保罗·阿尔陀的墨西哥友好城市瓦哈卡来的舞蹈演员。

But during those days, Harlem and Soweto were sister cities. 那时候哈莱姆和索维托可是友好城市。