PHOENIX (AP) — An Arizona man stumbled upon a trove of historical documents possibly worth thousands of dollars after purchasing an abandoned storage unit for $20 in a Phoenix suburb.

The Arizona Republic reports Don Smith discovered a collection of about 200 letters belonging to Henry Ellsworth Barbour, a Republican congressman from California from 1919 to 1933.

The collection includes two letters signed by President Herbert Hoover, White House invitations from President Warren Harding and an invitation to groundbreaking ceremonies for the Golden Gate Bridge.

He also found a congressional gav...