Aside from full-time residents and their families as well as building staff, hardly anyone has been inside the Bangor House at the corner of Main and Union streets in downtown Bangor for more than 40 years, ever since it was turned into apartments in the late 1970s. But in its heyday in the 19th and early 20th centuries, the Bangor House was one of the grandest hotels in Maine, with an ornate ballroom, a granite piazza, an elegant dining room, and even indoor plumbing — something truly novel for the 1830s.