In 1978, another kind of buried treasure was discovered when a construction excavation inadvertently uncovered a forgotten collection of more than 500 discarded films on highly flammable nitrate film stock from the early 20th century that were buried in (and preserved by) the permafrost. These silent-era film reels, dating from "between 1903 and 1929, were uncovered in the rubble beneath [an] old hockey rink". (See Dawson Film Find.) Owing to its dangerous chemical volatility, the historical find was moved by military transport to Library and Archives Canada and the U.S. Library of Congress for both transfer to safety film and storage. A documentary about the find, Dawson City: Frozen Time, was released in 2016.
