On the southern fringe of Boston's Back Bay resides one of the city’s most beautiful open spaces. A tranquil, 700-foot-long reflecting pool stretches out across Christian Science Plaza, which is home to two churches. Completed in 1894 by architect Franklin I. Welch, the Romanesque-style Original Mother Church features stained-glass windows that depict Bible Stories. The other church, Mother Church Extension, was designed in the Italian Renaissance style in 1906 by Charles Brigham and has a Byzantine-style dome and one of the largest organs in the world. Tours of both churches are free.