Stampy's secret base is deep under the lake beneath Stampy's Lovely House. It was first seen in Water Elevator. It can be entered in two ways, one is to dive down the water elevator under the lake, the other way is to go through a painting, climb down some ladders, and enter the code to open the iron door. Inside the base there's lots of gadgets and things that Stampy has built.
The main reason for the base is to help Stampy hide from Hit the Target in case of an attack. In the base, Stampy have the most advanced things in the lovely world. Stampy can also safely watch over the entire lovely world from there.