Tallest of a cluster of buildings in the middle of the common, standing tall with a set of recently-repaired sails, Wimbledon Windmill was built in 1817. It's of an unusual type too, originally a hollow-post mill, in this case an octagonal brick base supporting a conical tower with an iron shaft at its centre. Operations continued until 1864, after which the machinery was removed and the interior converted into living accommodation for six families. Since 1976 it's been a museum, and a surprisingly good one too, with the usual £2 entry fee waived this year because of the bicentenary.
The museum contains a seriously impressive collection of models, illustrating all the significant types of English windmill (using local examples wherever possible). Several of the sails turn at the push of a button, which is good news if you're a small child with a low attention threshold, and the timeline runs right up to modern wing rotors and aero generators. There's also a small room brimming with wooden tools gifted by a retired Norfolk carpenter, including numerous planes, the odd auger and a single snail brace countersink.
Upstairs the display gets a bit more Wimbledon-specific, including some cutaways, a lot of milling equipment and an evocative recreation of one of the Victorian living rooms. A central cabinet celebrates Robert Baden Powell, who was staying in the adjacent Mill House when he wrote Scouting for Boys in 1908, as a plaque on the exterior confirms. As a finale a steep ladder ascends into the tower to a wooden platform where a large cast iron brakewheel can be seen, as well as two further out-of-bounds ladders climbing precipitously to the top.
It's amazing quite how much has been crammed inside the former windmill, and how diversely informative it is, so do be sure to thank the museum's founder and curator if you're lucky enough to meet him inside perched by his desk. You might also like to know that the small shop just inside the entrance sells not just mill-related stuff but also a selection of cuddly Wombles, because that's exactly what a shop in the centre of Wimbledon Common needs. The museum is open every Sunday, and on Saturday afternoons, until the end of October, and bicentenary year is evidently the perfect time to visit.