In Stirling condition...

This annual event at Kew Bridge Steam Museum showcases more than 80 Stirling and hot-air engines. You can see model and full-size machines powered by coal and solar energy and meet the experts and enthusiasts who tend the period pieces.

Kew Bridge Steam Museum, Green Dragon Lane, Brentford, Middx (020-8568 4757). Sun 3 Apr, 11am-5pm, £5.20, child £3, concs £4.20, family £15.95 (to venue).