Agartha
https://en.wikipedia.org/wiki/Agartha

Utgard
https://en.wikipedia.org/wiki/%C3%9Atgar%C3%B0ar
https://en.wikipedia.org/wiki/J%C3%B6tunn

Biringan City
https://en.wikipedia.org/wiki/Biringan_City

Scholomance
https://en.wikipedia.org/wiki/Scholomance https://en.wikipedia.org/wiki/Scholomance

The City of Caesars
https://en.wikipedia.org/wiki/City_of_the_Caesars

Lost City of Z
https://en.wikipedia.org/wiki/Lost_City_of_Z

Hy-Brasil
https://en.wikipedia.org/wiki/Brasil_(mythical_island)

Youdu
https://en.wikipedia.org/wiki/Youdu.

Zerzura, The White City
https://en.wikipedia.org/wiki/Zerzura

The Nameless City
https://en.wikipedia.org/wiki/The_Nameless_City
https://en.wikipedia.org/wiki/Iram_of_the_Pillars