Looks good, I'll try one:

Name: Atlantisphere
[img]http://i.imgur.com/l1irpEs.jpg[/img]

Size: Half a Football Field

Properties: Made from an unknown material from the long-lost city of Atlantis, besides being almost indestructible it's covered in a force-field, making it impossible to break from the inside, although it's impenetrable the Atlantisphere is still somewhat translucid

Player Capacity: Most used in 1v1, but 2v2s are also possible

Flavour Text: Built long ago by the Atlanteans, the Atlantisphere was built for containing purposes, used firstly as a silo for highly dangerous materials, but later it was used by great warriors to prove their value to other heroes and Atlanteans, it was the stage of many epic battles in the past, it's said that past heroes who fought in this Dome have the right to watch the battles from the Afterlife