Aincrad
An Incarnating Radius, or much known as "Aincrad" is a giant floating castle consisting of 100 floors stacking straight upwards. Each floor has medieval-themed setting with a couple of large cities along with countless small scale towns and villages, forests and plains, and even lakes. Only one stairway links each floor to another, and the stairways exists beyond the boss room of each dungeons. In order to advance to the next higher floors, players must defeat each boss at the end of each floor.