What’s in the Museo Geominero? Well, pretty much everything that’s ever been dug out of the ground in Spain. Minerals, fossils, dinosaur bones, human skulls and arrowheads. This delightful but little-known Madrid museum also boasts a stunning collection of precious stones from around the world.

The building itself is amazing; the stained glass ceilings and four floors of galleries which are flanked with beautiful display cabinets are a visual treat. You access the galleries by tiny corkscrew staircases; the kids will love it!

Another plus is that it’s nearly always empty, and it’s usually an oasis of peace. There are red velvet banquettes where you can sit and write your postcards or edit your Instagrams or whatever if you are really not interested in minerals. Saturday is the busiest day, but even then it’s pretty peaceful. Also, it’s right by Calle Ponzano of cool restaurant fame, so if you have half an hour to kill before Spanish lunchtime starts (14:00) step inside the Geominero Museum.

Oh, and did I mention it was free? I know! Don’t forget I.D. though – they won’t let you inside without some.