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
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".
As the congregation runs towards the checkpoint, Blaine tries to convince his father to watch from the safety of a nearby rooftop in episode 4x13 "And He Shall Be a Good Man".
Lincoln escorts the shapeshifter from the warehouse when the team is fired upon in episode 4x17 "Everything in Its Right Place".