The legendary City of Gold is the final goal of Spelunky Classic, and an important part of a special run through Spelunky HD and Spelunky 2. As the name suggests, the City of Gold is made entirely of solid gold, and destroying the terrain of the city yields loads of valuable Treasure.
The City of Gold is situated within the Temple, and as such, it shares many (but not all) of the same hazards, including Croc Men, Mummies, and, in Spelunky HD, Anubis II. In Spelunky 2, Leprechauns carrying Four-leaf Clovers can be found, as well as Giant Crush Traps.
Accessing the City of Gold can be somewhat of a herculean task, especially in Spelunky Classic and Spelunky HD. Opening the door to the City of Gold, found on level 4-2 of the Temple, requires the use of the Scepter, alongside either the Hedjet or the Crown, both of which have their own prerequisites.
Within the City of Gold, one may find a Golden Statue in Spelunky Classic, the Book of the Dead in Spelunky HD, or an Altar in Spelunky 2. In Spelunky HD, the Book of the Dead is to be used to find the entrance to Hell in the next level - Olmec's lair. In Spelunky 2, the altar is used to sacrifice oneself in order to enter the Duat, providing the sacrificed is carrying the Ankh. If the City of Gold is departed via its normal exit, it simply leads to level 4-4 of the Temple, rather than the Duat.
For more specific information on the appearance and dangers of the City of Gold in the Spelunky series, see the pages below.