I didn't expect it to be so busy. I had about 3 ho...

I didn't expect it to be so busy. I had about 3 hours to kill in centre of Madrid. I came to the museum only to find a massive queue for the tickets. After 15 mins in the queue I noticed a message on the screen saying that they limit the amount of people they let in, so the next available slot was in an hour and half. I realised that by the time, I'd get to actually buy a ticket, my slot to go in would likely be around the time I would need to leave for my train.
Museum itself looks very professional and they exhibit famous artists, but one needs to be prepared to waste a lot of time, just to get in.