The Washington Temple for the Church of Jesus Christ of Latter -Day Saints will be 20 years old in November 1994. Architect Keith Wilcox says that he used Mormon teachings to draft the temple's design. Drivers on the Washington Beltway cannot miss seeing the temple, which is topped by six soaring spires, but those worshiping inside cannot see out. The building has no windows, but its marble facade is shaved in places to a half-inch thickness, allowing light to shine through the walls. The temple is reserved for the holiest of Mormon rituals. It is not open to non-Mormons , and not even all Mormons are permitted inside. The Washington Temple serves a district of 300,000 faithful that extends from New England to North Carolina.