After the exotic experience of finding yourself in a jungle growing inside a train station, you'll find a very different atmosphere at the Memorial. This monument was erected in memory of a dramatic attack, or more precisely, a series of explosions that on March 11th, 2004 resulted in horrible tragedy in the Atocha Station at just before eight in the morning, at a busy commuter time. Subsequent declarations of responsibility revealed that terrorists were behind the attack.
You are now at the entrance, which is wrapped in evocative cobalt blue tones. You saw the monument's external structure above ground when you were in front of the station. It was inaugurated in 2007.
After the short hallway where you can read the names of the nearly two hundred victims, you enter a large, light room through a double door that's necessary for maintaining the room's internal pressurization. The only illumination here comes from the central light that filters through a glass dome to illuminate the eleven meters of the cylindrical tower that's covered by a transparent membrane. Inside it, you can read thousands of messages of condolence written on notes in all the world's languages. Reading the phrases on the opaque curved walls evokes strong emotions. Note also the intensity of the effect the monument seems to communicate: even though you're underground, it almost seems to rise up to the sky, taking you up with it.
FUN FACT: the Memorial is acoustically isolated. You'll notice it right away, as you find yourself immersed in a silence that almost lets you physically feel commotion for the victims.