Riverside Church that were not built specifically for the church. Stairs leading both upward and downward are on the eastern side of the narthex, and a mortuary chapel is on the northeastern corner. The mortuary chapel is known as the Gethsemane Chapel but prior to 1959, it was called the Christ Chapel. Chapel The chapel to the south of the narthex, which since 1959 has been known as the Christ Chapel, was inspired by the Basilica of Saints Nazarius and Celsus in France. Its design was inspired by the pointed Romanesque nave at Carcassonne Cathedral. The design, which was described by architectural historian Andrew Dolkart as "earlier than Gothic", is intended to give the impression the rest of the sanctuary was built after the chapel. The chapel is subdivided into four bays and has a barrel-vaulted ceiling with Guastavino tiles, and the walls and floor have a limestone finish. The southern wall, which is adjacent to the MLK Wing, has four arched, back-lit stained-glass windows; one in each bay. Double doors to the west lead to Riverside Drive and a passage to the south leads to the MLK Wing. There are engaged columns on the north and south walls between each of the four bays, and eight lanterns hang from the columns. The eastern end of the chapel contains an altar, four steps above the chapel's main level. There is a lectern to the right of the altar and a pulpit to the left. Several sculpted representations are above the altar. Behind the altar are a baptismal pool and a reredos, which are accessed through an arched opening. An alcove to the narthex is north of the altar. Tower and carillon The tower was named after Laura Spelman Rockefeller, the mother of John D. Rockefeller Jr. The tower contains 21 usable floors, which include 80 classrooms and office rooms. There are four elevators, of which two rise only to the 10th floor, whereas the other two rise to the 20th floor. The 20-floor elevators, which rise , were described in 1999 as the world's tallest elevators inside a church. Two staircases ascend from ground level; one on the western side of the tower ends at the ninth floor, and the one on the eastern side continues to the carillon. Balconies are at the southern corners on the 8th floor and on all sides of the 10th floor except the north