An island in the Widewater section of the Chesapeake & Ohio Canal National Historical Park. (All photographs by H. Darr Beiser)

Nature somehow always gets the last laugh. The Chesapeake & Ohio Canal was built to conquer the navigational challenges of the Potomac River for commerce. Construction took 22 years, and the 184.5-mile canal, from Georgetown to Cumberland, Md., was completed in 1850.

A doe jumps into a shallow portion of the canal to cross the water.

It had a heyday, then the Baltimore & Ohio Railroad opened, the Civil War erupted and two disastrous floods struck. The last commercial boats traveled it in 1924.

A young tree grows amid the machinery of an old lock on the canal.

Today the canal is a buffer that protects the river from human development. Thanks to the establishment of the Chesapeake & Ohio Canal National Historical Park in 1971, much of the Maryland side of the Potomac is spared from construction of homes and highways. Although the canal is man-made waterway, it has become a haven for flora and fauna.

A mallard spreads its wings.

The water-filled section of the canal, stretching northwest from Washington to Riley’s Lock 17 miles from the D.C. line, is rich with wildlife. The towpath and other trails in the park are crowded on weekends, so if you can, go for a stroll on a weekday. Take your time. You might be surprised by the nature you see.

A great blue heron stands on a fallen tree branch.

H. Darr Beiser was a founding member of the photography staff of USA Today when the newspaper launched in 1982 and worked there until 2015. Since then he has been training his lens on nature near his home in Bethesda, Md.