The Cathedral Church of Saint Peter and Saint Paul in the City and Diocese of Washington, operated under the more familiar name of Washington National Cathedral, is a cathedral of the Episcopal Church that was constructed between 1907 and 1990.
The cathedral contains 231 stained-glass windows completed by a variety of artists; although over 40 were designed by Rowan LeCompte. The colors and subjects of the windows are diverse from biblical scenes to civil war scenes to a description of space containing a moon rock brought back to this planet by Apollo 11.
Following the completion of mock-ups, the failing caulking around the stained glass windows was removed and replaced. This included replacement of backerod. The colored glass surfaces were also cleaned using distilled water and highly absorbent sponges and towels. Select exterior windows were also caulked and cleaned as needed.