I. M. Pei's stark white concrete and dark glass building, completed in 1979, sits at the tip of Columbia Point peninsula with views straight back across Dorchester Bay to the city skyline — the kind of view a young Bostonian president would have wanted for his memorial. The library holds Kennedy's papers, plus Ernest Hemingway's literary archive (an oddity arranged through Jacqueline Kennedy and Mary Hemingway).
The museum on the lower floors uses 1960 newsreel footage, period photographs, and the actual desk from the Oval Office to walk through the campaign, the brief presidency, the Cuban Missile Crisis, and the assassination. The final room is a vast skylit pavilion with a single American flag — quiet, deliberately empty, the architectural equivalent of a held breath.
The site is a fifteen-minute walk from the JFK/UMass T stop, with a free shuttle bus connecting them. Combine with the State Archives next door if you have an interest in colonial documents.