Dredge No. 4 National Historic Site is 12.3 km (7.8 mi.) s. on Bonanza Creek Rd. This massive eight-story dredging machine rests alongside Bonanza Creek where it sifted millions of dollars' worth of gold from 1899 to 1959. The dredge was once the largest wooden-hull mining dredge of its kind in North America. Visitors can learn about the machine's history through interpretive panels in the parking lot as well as through a smartphone application, children's activity booklets and tablet rentals at the visitor center. Tours are provided by Goldbottom Mine Tours.