Lake Abydos

From Tardis Wiki, the free Doctor Who reference

Lake Abydos was a body of water on Gallifrey. It was home to singing fish. When Romana I was a young girl in her 60s, her family spent their summers at the lake, where she would swim and gather zinc hawthorns from the molten rushes at the water's edge. (AUDIO: Neverland)

Romana II facetiously asked Trave if the War Council had gigantic droids on the bed of Lake Abydos. (AUDIO: Celestial Intervention)