One of the gems of the Fenway neighborhood is the expansive campus surrounding Christian Science Plaza, home to several historic buildings that form the headquarters of the Boston-based Christian Science church founded by Mary Baker Eddy in 1879. What many may not know is that several of these beautiful edifices, including The First Church of Christ, Scientist, can be explored via free tours that take place every half hour on Tuesdays from noon–4 p.m., Wednesdays from 1–4 p.m., Thursdays–Saturdays from noon–5 p.m. and Sundays from 11 a.m.–3 p.m. Tours include visits to the Mother Church (pictured above, middle), a Romanesque structure built in 1894 that boasts gorgeous mosiacs, stained glass and a vintage pipe organ; and the domed Church Extension (above left), an enormous, Byzantine-Renaissance style house of worship erected in 1906 that seats 3,000 and houses the largest Aeolian-Skinner pipe organ in the world.