I might not be the most people-person ever, but if there is something that makes conventions extra fun, it is seeing attendees unapologetically geek out about what they love – in the case of Expominerales, that would be… rocks. Of course, this is an over-simplification. Expominerales is held yearly in the mine and energy engineering school Escuela Técnica Superior de Ingenieros de Minas y Energía (ETSIME) in Madrid. The year 2024 marks the 43rd edition of the event, which is considered one of the most important fairs in Spain in the topic of Earth Sciences – minerals, fossils, gems, and meteorites are widely available to the public. Aside from the small historical museum Museo Histórico-Minero Don Felipe de Borbón y Grecia, there were dozens of exhibitors with all kinds of items for sale, ranging from a few euro to several thousands. These year there were a few lectures, too, and coincidentally, the two of them I was most interested in happened on Saturday, one after the other.

I arrived at the ETSIME around 11:00, and I walked around the stands a couple of times. I have to say that I wanted everything, but I set a budget and I was able to stay around it, after shopping and lunch. At noon, I settled to listen to the lectures – one about the rehabilitation of an ancient gypsum mine in a hamlet called Hornillos de Cerrato, in the area of León. The other one versed about the uses of an already-rehabilitated one in the south of Spain, home to a huge geode. Both of them were pretty interesting, though the conference room was freezing. Someone had forgotten to turn on the heater there, it seemed…

After the two conferences, I had a last round to buy a last thing, so in the end I bought an iron-meteorite pendant, a fossilised shark tooth pendant, a plesiosaur tooth, and a soil sample of the K–T boundary. A plesiosaur was a marine reptile with flippers, a short tail and a long neck. The K–T boundary (now named the Cretaceous–Palaeogene (K–Pg) boundary) is the theoretical layer of iridium-rich black sand that was formed by the meteorite that caused the extinction of non-avian dinosaurs – and basically most life at the time, in one of the great world-wide extinctions in the history of Earth.

At 14:30, I had a reservation for lunch at a Japanese franchise called Ramen Shifu. While I had originally been looking forward to trying the ramen (and I got my hopes pumped up when I read that they were Hakata ramen style), the noodles were rather disappointing. Fortunately, the okonomiyaki – Japanese pizza of sorts, made with a base of cabbage and topped with sauce and bonito flakes, was all right. On top of everything, paying was stupidly difficult because they did not have change.

When I came out of the restaurant though, it was raining like crazy. I pulled out my umbrella and hopped towards the closest underground station, as my next destination was inside the metro system – one of the Underground’s museum network Museos de Metro de Madrid the collection of classic trains Estación de Chamartín: Exposición trenes históricos, inside the Chamartín stop. The exhibition displays four historical trains, restored from among the first ones that ran under the city, and some memorabilia. It was a bit underwhelming – more like false advertisement. I hoped I would be able to snoop inside the trains, since that was the photograph that opened the webpage, but unfortunately they were cordoned off. There was however a map with the works by Antonio Palacios in Madrid, which will become handy eventually.

Afterwards, I just headed off towards the train station and got back home.