In 1956, the first transatlantic cable was laid between Gallanach Bay, south of Oban in Scotland and Clarenville, Newfoundland.
The cable could carry 36 channels with 4kHz bandwidth, which was later reduced to 3kHz to allow 48 channels.
The cable landing station at Gallanach is still standing, and can be seen on Google Earth.
Photographs of the stripped interior can be seen on derilictplaces.co.uk.
According to this article http://exotc.org/2012/10/07/the-secret-submarine-cable/ the TAT-1 terminal equipment was located within the hillside for protection against attack. The article suggests that CANTAT-1 terminated at Oban in a windowed building on a cliff face, it is not known if this is the same location as TAT-1 terminates, although the building above would fit the description.
A new article form The Register has some further information on TAT-1, including the photo below showing the cable shrouded in concrete in the foreground.
The article is here.