Asgard

Asgard exists in a alternate dimension and is home to six different races. Asgard is an asteroid-like world suspended in a "Sea of Space". Gravity radiates from somewhere underneath this asteroid. The top of this "asteroid" is flat like a table. If someone stepped off of this "table", they would fall off the "asteroid" and down through space until they reached the "gravity-generator". Asgard can only be reached from Earth by crossing Bifrost, the Rainbow Bridge.