presence of large numbers of pilgrims, nighttime visitations, and the build-up of Chabad homes and facilities in the area has resulted in tension with the surrounding African-American community in the decades since Menachem Shneerson's death. Customs At the Ohel, visitors have a tradition of writing kvitlach – prayers on small pieces of paper – which are then torn up and tossed onto the graves. In the visitor's center, a fax machine receives over 700 faxes a day, while a computer receives 400 e-mails daily. These kvitlach are printed, torn into shreds, and placed atop the graves. When the pile grows too high, the shredded notes are burned. The visitor's center also receives many wedding invitations for Menachem Schneerson which are read at and/or placed on the graves. In addition to kvitlach, visitors are encouraged to light memorial candles at the Ohel. Visitors to the Ohel customarily light candles on shelves in the antechamber. Visitors also write letters to Menachem Schneerson beforehand and read them beside the graves, then rip them up and leave them on the graves. Kohanim According to Jewish law, a kohen (Jewish priest) is not allowed to ritually defile himself by entering a cemetery. Halacha mandates that the kohen be a distance of four amahs from a grave unless separated by a fence. The construction of fencing along the pathway leading to it makes it possible for kohanim to enter the Ohel. At the Ohel itself, the graves are open to the sky to eliminate problems of tumas meis ("impurity from the dead"; see Tumah and taharah) in an enclosure, and a low wall surrounds the graves and keeps the kohen at least 12.59 inches (320 mm) away from a tombstone to maintain his ritual purity. Gallery See also Ohel (grave) References Cambria Heights, Queens Chabad in the United States Jewish mausoleums Laurelton, Queens Menachem Mendel Schneerson Yosef Yitzchak Schneersohn