I recently visited the Tank Museum in Bovington, Dorset. As the name suggests, this is a museum of tanks from their origins in the First World War to the present day. The museum has the British prototype tank, Little Willie, and other First World War vehicles.
As well as British tanks, the museum also has a Renault FT from 1918, the first tank to look like a tank (with a rotating turret above the chassis).
There is an interesting First World War exhibit, including an atmospheric mock-up of a trench.
The German machine-gunners are quite striking when unexpectedly encountered.
The trench exhibit includes a modelled tank attack on a German position.
A tank museum is a bit niche but I think anyone with a passing interest in military history and armoured vehicles would find plenty to interest them at the Tank Museum.
More pictures (mostly of vehicles from the Second World War and Cold War).