The Cathedral of St. John the Divine: Located in Morningside Heights, St. John the Divine is one of the five largest Christian churches in the world. It measures 601 ft. long and 232 ft. high, the inside covering 121,000 sq. ft. Originally planned as Byzantine-Romanesque in design, construction on it began in 1892 though it was changed to a Gothic design in 1909. The cathedral has yet to be completed.