Question: Gilbert D. Hedden, was an American industrialist, politician and treasure hunter, and is most notable today for the progress he made in the 1930s, towards solving the treasure mystery at Oak Island, a 57 hectare privately owned island in Lunenburg County on the south shore of Nova Scotia, in which country?
Sentence (from "Gilbert Hedden"): and is most notable today for the progress he made in the 1930s towards solving the Oak Island treasure mystery, described as the costliest treasure hunt ever.
Relevant evidence: Yes