The Well of the Souls is the holding place of the Ark of the Covenant. In 1936 Indiana Jones and Sallah attached the Headpiece to the Staff of Ra and brought it to the Map Room in Tanis, Egypt. Indy lets the sun shine through the headpiece in order to reveal the location of the Well of the Souls. This allowed Indy and Sallah to discover the Ark of the Covenant. After finding the Ark, Sallah and the Ark were hauled out, but Marion Ravenwood was dumped into the well by Toht, Colonel Dietrich, and Gobler, against Belloq's wishes.
In Lego Indiana Jones: The Original Adventures
In the LEGO game, Indiana Jones (Desert) and Sallah (Desert) work together to pass many obstacles and traps to get to the Ark. As in the film, Marion is thrown into the Well of the Souls and Indy and her have to find a way out together. The Boss for the Level is the Basilik.