We can use ここ, そこ and あそこ to talk about locations without naming them.
ここ is used to refer to a location close to the speaker. そこ is used to refer to a location close to the listener. あそこ is used to refer to a location that is neither close to the speaker nor to the listener.
|Where am I?||私 は どこ です か？watasi ha doko desu ka?|
|(I) am here.||ここ です。koko desu.|
|You are there.||あなた は そこ です。anata ha soko desu.|
|The ball is (over) there.||玉 は あそこ です。tama ha asoko desu.|