1..I still remember the park.we first met 2..This is the park.we visited last weekend.

1 where We first met in the park(park为met的地点)
2 which we visited the park (park 为visited的宾语)不是in which =where 吗 ，没有in啊你很聪明！ 你把原句分解成两句：1I still remember the park.we first met (in the park) 故 where 取代in the park