Grid sizes

I like to know what is the very maximum grid UE4 goes up to, can it max out at 1,000,000 by 1,000,000 quads, if 1 quad is equal to 1meter, 1,000 quads equal to 1km, then 1 million quads 1,000 kms nearly large enough to fit Australia will UE4 get that advanced, also is the maximum hight virtacies 30,000 ft yet to build Mout Everest, also can UE4 create the Marianas Trench and sorry about the spelling?