Atlantis is an island city. It is said to be the sort of place one never wants to leave. While its Earth One counterpart is considered a "lost city" due to it seemingly being submerged in the ocean, Atlantis on Earth Two is above water.
Hunter Zolomon admitted to loving Atlantis, especially as one of his best friends originated there.
When Harrison Wells opened a map of his world, a large island, presumably Atlantis, was visible west of Europe.
Barry got his parents plane tickets to Atlantis for their anniversary.
After Barry and Iris helped Team Flash free Jesse and Earth One Barry from Zoom, they temporarily relocated to Atlantis to stay with some family members to escape from the evil speedster.