layers of sealant. The Director of Music and organist is Christopher Johnson . Past organists at the Riverside Church include Virgil Fox (1946–1965), Frederick Swann (1957–1982), John Walker (1979–1992), and Timothy Smith (1992–2008). Art and sculpture Paintings Paintings by Heinrich Hofmann that were purchased by Rockefeller Jr. and donated to the church in November 1930 are displayed in the building. Christ in the Temple (1871) and Christ and the Young Rich Man (1889) are displayed in the assembly hall beneath the nave, and are usually locked within the cabinets there. Hofmann's Christ in Gethsemane (1890) is displayed the Gethsemane chapel. Stained glass Riverside Church's main building contains 51 stained glass windows, excluding small grisaille windows. These were created in a mosaic style, which was becoming more popular at the time of the church's construction. Of these, 34 windows are in the nave; most of them include religious iconography. Generally, the richly colored windows are on the building's western side, which is considered the "light" side, while those with muted colors are on the eastern "dark" side. French glassmakers Jacques Simon from Reims Cathedral and Charles Lorin from Chartres Cathedral were hired to create the glass for the clerestory windows in the nave. Lorin designed the stained-glass windows on the western side of the clerestory while Simon designed those on the eastern side. Both sets of windows depict general religious and governmental themes, and also incorporate secular iconography and depictions of non-Christians. The clerestory windows closely resemble those at Chartres and include a rose with lancet windows. The other windows in the nave were created by Boston-based firm Reynolds, Francis and Rohnstock and depict 138 scenes with both religious and non-religious contexts. The three groups of stained glass windows in the apse and the nine stained glass windows in the South Hall were created by Harry Wright Goodhue. Mosaics Gregor T. Goethals created two mosaics for the fourth and seventh floors of the MLK Wing. The fourth-floor mosaic depicts events described in the Old Testament while the seventh-floor mosaic depicts the Creation story. Sculpted elements Exterior elements The building's most prominent sculptural details are on the Riverside Drive facade. The main entrance beneath the tower is topped with five concentric archivolts with sculptures of Jesus's followers and prophets inlaid within each section. The third arch of the main entrance has depictions of philosophers including Ralph Waldo Emerson, Immanuel Kant, and Pythagoras,