Chamberí ghost station, Avisos
After being at the Fernán Núñez palace earlier, where, as usual, pictures were absolutely prohibited, I felt really surprised when our tour guide at the Chamberí ghost metro station said that pictures were permited. She said "Please, take advantage of it! At least HERE you can take pictures...". She totally made my day!
This announcements sign had some original printings with maps and ticket fares. At the time there were 2 lines, and the price of the ticket was around 10 cents of peseta, which is about 0.0006 € or 0.0008 USD. Now there are 12 lines with 292 stations and 287 km of rail, making it the 8th biggest subway network in the world. The price is 1 €, which is pretty cheap, in my opinion.
Walls were covered with white tiles, to reflect light. The light in the restored station is supposed to be a little bit brighter than it was in 1919, but still it was really dark (on purpose).