Start at the Amsterdam Avenue entrance and take some time to examine the Portal of Paradise, which features a carving of Christ enthroned in glory. Under that is a carving of St. John, with the two main front doors on either side. The doors are flanked by carvings of Biblical figures. Since the building's only two-thirds complete, you'll notice there are plenty of spots where sculptures or other architectural elements are missing.
Enter the church and work your way around clockwise. Hard to your left is the Poet's Corner, but unlike the more famous Poet's Corner in Westminster Abbey, there's only memorials here. The chapels along the nave are dedicated to various career fields. On the left-hand side they include sports, the arts and education.
Step up to the columned area to the east. The choir section is executed in a Romanesque style below and a Gothic style above. Beyond it is the Historical Parapet, which includes statues of Washington, Lincoln, Gandhi, St. Paul, St, Augustine, Einstein and Martin Luther King. Beyond this is the high altar, which is flanked by menorahs. Though this is technically an Episcopalian church and the Seat of the Episcopalian Bishop of the Diocese of New York, St. John's is a very ecumenical and inter-religious gathering place.
Cross the unfinished transepts. The last doorway to the left before the choir leads to the octagonal baptistery. The marble font and other work here was paid for by descendants of Dutch Governor Peter Stuyvesant. Work your way around the apsidal chapels of Saints Ansgar, Boniface, Columba, Saviour, Martin, Ambrose and James. Called the "Chapels of the Tongues," they are dedicated to Scandinavian, German, English and Celtic, Eastern, French, Italian and Spanish immigrants to New York. The altarpiece in St. Saviour depicts the life of Christ and was executed by Keith Haring shortly before his death.
Continue from the Chapel of St. James, through the special exhibition hall and back into into the transepts, then west through the nave. Among the side chapels on this side are ones dedicated to firefighters, people in the military, journalists and victims of genocide. When you get back to the west end of the nave stop by the gift shop, which is a major source of St. John's income and was severely damaged in a 2001 fire.
Go outside and explore the grounds. South of the church are several other buildings, including the past and current residences of the Bishop, Diocesan offices and a school. There's also an outdoor pulpit, a garden featuring plants grown in Israel in Bible times and the Children's Sculpture Garden with images of animals. The Peace Fountain depicts St. Michael the Archangel and Satan battling it out while animals, the sun and the moon look on.