Episode 4Series Episode Number: 148
World Premiere: Sat 4 Feb 1967 - 5:50pm GMT [BBC One] (United Kingdom)
Running Time: 23 minutes 20 seconds
7.00 Million (UK)Appreciation Index: 47 (UK)
Chart Position: 65 () (UK)
Recorded on Fri 28 Jan 1966 in Riverside 1
Archive State: Missing
As Zaroff's insane scheme to destroy the world nears completion, the Doctor plans to break down the sea wall and flood Atlantis.