Rowing in Retiro Park is a favourite for Cian’s grandkids.
Plaza de Espana is about a fifteen-minute walk, past the Royal Palace, and this gets the grandkids’ vote as the best playground in the locality, although it can get crowded just after school gets out.
The Railway Museum is good fun. As well as a large collection of steam, electric and diesel engines, it has a lot of related exhibits: carriages, line maintenance equipment, a stage coach, and an extensive model railway.
Museum of San Isidro is just around the corner from the apartment in Plaza de los Carros, and it is definitely worth a visit. Entry is free. It covers the history of Madrid from prehistoric times until 1531, when it became the capital, with lots of mastodon teeth and mammoth tusks. It has an interesting display about the various walls which were built around the city, and also one on the origins of La Latina hospital. It’s also got a special section on St. Isidore, the patron saint of Madrid, who lived here while working as a farm hand (labrador), tending cattle for the Vargas family and where a number of miracles happened.
The Robot Museum is OK for a rainy day. It’s not very interactive: the guide tells you about each robot and what was novel about it, and then there is a short period at the end where the kids can try to get one of the robots to perform a task.