A permanent exposition in the Convento de San Francisco de Asís' Salón Blanco (use separate entrance on the church’s south side behind the Coche Mambí) that has cleverly built mock-ups of many of Leonardo’s famous drawings – gliders, odometers, bikes, parachutes and tanks – the antecedents to pretty much half the inventions in the modern world.
It’s beautifully laid out with explanations in six languages, including Russian.