One of the most fascinating historic landmarks that we've visited since moving to Boston is the Ether Dome in the Bulfinch Building at Massachusetts General Hospital.
It was the hospital's first operating room in which ether (a highly volatile chemical) was used as a anesthetic on a patient with a tumor in his neck. Dentist William Thomas Green Morton administered the ether to the patient, Edward Gilbert Abbot. The tumor was removed by the dean of Harvard Medical School, John Collins Warren.
The best part of the story is when the dean turned to the medical audience and said,
"Gentlemen, this is no Humbug"
Which was a reference to the year before when a different type of anesthesia evoked cries of "HUMBUG!" from the patient.
The Ether Dome is one site we've been to several times and are always fascinated by the history and space. The surgical tools on display are also disturbing and worth a look. The Ether Dome is highly recommended. It's free and open to the public.