Wikipedia's page for Smithson (
visit link) has this to say about the crypt:
"Smithson was buried just outside Genoa, Italy. The United States consul in Genoa was asked to maintain the grave site, with sponsorship for its maintenance coming from the Smithsonian Institution. Smithsonian Secretary Samuel P. Langley visited the site, contributing further money to maintain it and requested a plaque be designed for the grave site. Three plaques were created by William Ordway Partridge. One was placed at the grave site, a second at a Protestant chapel in Genoa, and the last was gifted to Pembroke College, Oxford. Only one of the plaques exists today. The plaque at the grave site was stolen and then replaced with a marble version. During World War II, the Protestant chapel was destroyed and the plaque was looted. A copy was eventually placed at the site in 1963. The grave site itself was going to be relocated in 1905, and in response, Alexander Graham Bell, who was a regent for the Smithsonian, requested that Smithson's remains be moved to the Smithsonian Institution Building. In 1903, Bell and his wife, Mabel Gardiner Hubbard, traveled to Genoa to exhume the body. The ship departed Genoa on 7 January 1904 with the remains and arrived on 20 January. On 25 January a ceremony was held and the body was escorted through Washington, D.C. by the United States Cavalry. When handing over the remains to the Smithsonian, Bell stated:
"And now... my mission is ended and I deliver into your hands ... the remains of this great benefactor of the United States.”
The coffin then lay in state in the Board of Regents' room, where objects from Smithson's personal collection were on display."
and this to say about Smithson:
"James Smithson, MA, FRS (c. 1765 – 27 June 1829) was an English chemist and mineralogist. He was the founding donor of the Smithsonian Institution.
Smithson was the illegitimate child of the 1st Duke of Northumberland, and was born secretly in Paris, on an unknown date, possibly in the Pentemont Abbey, as Jacques-Louis Macie (later altered to James Louis). Eventually, he was naturalized in England and attended university, studying chemistry and mineralogy at Pembroke College, Oxford. At the age of twenty-two, he changed his surname from Macie to Smithson, his father's pre-marriage surname. Smithson traveled extensively throughout Europe publishing papers about his findings. Considered a talented amateur in his field, Smithson maintained an inheritance he acquired from his mother and other relatives.
Smithson was never married and had no children; therefore, when he wrote his will, he left his estate to his nephew, or his nephew's family if his nephew died before Smithson. If his nephew was to die without heirs, however, Smithson's will stipulated that his estate be donated to the founding of an educational institution in Washington, D.C., in the United States. In 1835, his nephew died and so could not claim to be the recipient of his estate; therefore, Smithson became the founding donor of the Smithsonian Institution in Washington, D.C. despite having never visited the United States."