Aridius is a planet in a binary star system that was once completely covered by oceans; its orbit around its suns was altered, causing to become a desert. The only remaining species are the amphibious Aridians and the octopus-like Mire Beasts. It is the setting for the beginning of (DW: The Chase)
The First Doctor visited Aridius, but was tracked by the Daleks.
The Daleks later returned to Aridius, still remembering their encounter with the Doctor there. They wanted revenge on the Aridians and wiped them all out along with the Mire Beasts. (DWBIT: #41 - Dalek Wars)