This school was founded in 1869. As the floor of the school is a bit higher from the ground, you need to cross some stairs to enter into the school through the blue colored door.
Sarah Fuller, the principal of the public Horace Mann School for the Deaf (formerly known as the Boston School for Deaf Mutes) invited Alexander’s father to train Fuller's instructors and introduce the Visible Speech System to them. However, Bell’s father declined the post and offer his son, Alexander Graham Bell to take the responsibility.
Source: Wikipedia
Helen Keller moved to New York in 1894. She went there in order to learn from the principal of the public Horace Mann School for the Deaf, Sarah Fuller.
Source: Wikipedia