As any land agent can tell you, it's all about location. Historicaly good locations for mythical real esate include at the uncharted headwaters of a great river ( Nile, Amazon ) -- great for lost cities, and unknow mines. Deep in the dessert/ mountains -- like the Seven Cities of Gold in the North American southwest, Dank Dark Jungles ALWAYS have odd cities, hidden lands and wonders unheard of -- the fountain of youth, or the city of the Amazons. The Center of the Earth, and Deep inside the moon, and deep inside Mars have all been claimed.

The Norse had this thing with tree roots and lands over the rainbow. Or was that Dorothy?

Uncharted islands are popular -- that is where Lilliputians live, the Lotus Eaters, Circie, and Cyclopes roamed; and where Gilligan landed.

We could go thru a piece of everyday household furniture to get there -- Looking Glasses, Wardrobes, and pictures have been used. I think flying an entire house over the rainbow is just a bit much, though.

Perhaps we need a special means of locomotion to arrive -- jump down a rabit hole, take a potion, eat a cookie, or use one of our Bedknobs, footstools, or find platform 13 1/2 to catch the magic train. Of course we could fly, but have you ever tried to talk a pixie out of enough dust to commute to work on Monday?

I think my favorite location is Somewhere Familier like Your Own Backyard -- but magical, like Camelot.