Johns Hopkins Hospital is not a tourist attraction in the conventional sense, but the main dome building — Billings Hall, completed in 1889 — is an architecturally significant structure that is worth seeing from outside. The dome is visible from several approaches to the medical campus and makes a distinctive landmark in east Baltimore.
The hospital is internationally famous as the institution that in effect created modern medical education in the United States. It remains one of the highest-ranked hospitals in the country. The campus has expanded enormously from the original buildings, but the historic core is preserved and accessible. Worth a photograph from the exterior at least.