Cromer

Cromer was a location to which the Brigadier believed UNIT headquarters had once been transported. It was probably in Norfolk. (DW: The Three Doctors)

When the Timewyrm sent Ace into the Doctor's mind, the landscape at first resembled a pier in Cromer. (NA: Timewyrm: Revelation)

Behind the scenes
In real life, Cromer is in fact situated on the Norfolk coast — a fact implied, but not directly stated, by the script of The Three Doctors.