According to TheaterOrgans.com, the Wanamaker Organ was built by the Los Angeles Art Organ company for the 1904 St. Louis World's Fair. The cost reached $105,000 and bankrupted the builder.
In 1909, John Wanamaker bought the instrument for his Philadelphia emporium and it was freighted from St. Louis where the installation took two years, after which it was greatly enlarged to fill the large space it occupied.
Virgil Fox on the Wanamaker organ:
Read more at Wikipedia.
Read more at Friends of the Wanamaker Organ.