Built in 1873 as one of the Palmerstone Forts, it first saw action against the French in 1873. During WW2 it was heavily manned and was a major defence against German air attack with numerous guns able to open up.
The fort played a major part in the Dieppe raid:
'August 1942 saw Newhaven playing a major part in the ill-fated Dieppe Raid, described officially as a 'reconnaissance in force'. Some 5,000 troops, for the main part units of the Canadian Army, but also with British Commandos and a small token force of US Rangers, had as their objective, the capture of the French port of Dieppe, which they were to hold for 24 hours and then withdraw. Of those 5,000 only 1,400 returned from the raid. Troops and tanks taking part had left from Newhaven and most of the returning survivors came back to the port. Among the casualties was Lieut. Edwin Loustalot of the US Rangers, the first American soldier to be killed in Europe during the war.'
The fort closed as military establishment in the 1960's and fell into neglect. However it was done up and opened to the public in 1988. Theres plenty of bits and pieces to have a nose around. My favourite being the ROC Post reconstuction and the various bits and pieces they have on display..