"Avoid this hotel. I booked BYPILLOW Castellana because of its location and because it advertised air conditioning. With Madrid at 35°C, this was essential. At check-in, I specifically asked the receptionist to confirm the air conditioning was working and was assured everything was fine. It wasn’t. The air conditioning did not work, the room was unbearably hot, and I endured one of the worst nights I’ve ever had in a hotel. The following morning I was then told the air conditioning was broken....

"Nice, clean, and conveniently located. The space is a little tight, but then again, those of us used to larger accommodations in the US need to remember that things are properly-sized in Europe."