Barry lands in an alley after throwing the stone into the Speed Force only to realize he is in the future in episode 3x09 "The Present".
Source: fakedestielfan — Twitter
Alleyway on Fuller
A stranger arrives from another Earth looking for H.R in episode 3x10 "Borrowing Problems from the Future". Cisco arrives with Ralph and creates a breach in the alley to help Nora escape Cicada's dagger in episode 5x17 "Time Bomb".