The Nexus of All Realities exists in the Florida Everglades. It was initially opened in the early 1970s by Jennifer and Andrew Kale.
While the gateway in the Everglades is generally referred to as 'The Nexus of All Realities', other possible Nexus points have been suggested, including the M'Kraan Crystal, and an unspecified point in deep space. Another Nexus is located on an unpopulated red-brown planed called Makray, into the Milky Way.
All these nexuses are multiversal and supposedly exists in all realities simultaneously.
The Nexus of All Realities located in the Everglades has been consistently protected for years by the Man-Thing, who is currently its sole guardian. Many different creatures, aliens, and humans have been sucked into different nexuses (the most well-known example being that of Howard the Duck), and placed into the Everglades, with many of them having to deal with Man-Thing. Man-Thing can also use the gateway as a sense of teleportation to travel through different alternate realities.