Not all English Heritage properties are open yet, and those that are require pre-booking via their website.
If you, or any of your party have a new persistant cough, or develop a fever of 38C, we would instead advise you to use the NHS's dedicated website for professional advice.
One of Henry VIII's coastal forts, re-modelled and extended in the 17thC in French style. The best and largest example of 17thC military engineering in England, showing the development of fortifications over the following 200 years. Exhibitions, the powder magazine and bunker-like casemates show how the fort protected London from seaborne attack.