Thor laughed. "This is not Asgard, though there is a path to Asgard should you wish to go. This is some crossroads between the realms," he explained. "And I fear I am not the best person to explain it to you. We refer to it as the Nexus."

It was not one of the nine realms that he was familiar with but seemed linked to all; Thor had no trouble traveling between the Nexus and Midgard or the Nexus and Asgard. It really was a door between the realms.