Opar.  Beast-men.  Beautiful women.  Gold.  Jewels.  What’s not to love?  First described in Edgar Rice Burroughs’ Tazan Returns, it plays prominently in several of his other adventures, not the least of which is Tarzan and the Jewels of Opar.  Both available free from Manybooks.net.  My most popular book here is Princess of Amathar.