This stretch of beach along California's central coast is a busy highway for the largest seal in the northern hemisphere.

The unbelievably opulent home built for an infamous newspaperman.

A massive volcanic plug is now a protected area that hosts a number of bird species.

Happy harbor seals frolic and snooze on this warm, sandy stretch of coast.

A dramatic coastline that’s home to a rare pine tree.

An ode to the friendship between four Pacific Rim countries.

A blast from the past in central San Diego.

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

The Grand Canyon of Texas.

17,400 lbs., 12 feet in diameter, and 29 years in the making.

This posh mansion began as a family's estate and ended as the site of a murder ripped from the pages of a pulp novel.

This rare vessel mixed luxury with labor before being converted to a museum and sometimes haunted maze.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

This freshwater spring fills with 10,000 gallons of water per minute.

Michigan's first reclaimed art sculpture lounges along the Upper Peninsula's Manistique River.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

A tunnel that brings more than a century of history to life from the deepest parts of the Niagara Gorge.

One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

A 13,000-year-old mastodon skeleton was found during the construction of a 19th-century New York mill.

This stained glass window designed by Tiffany Studios is hidden behind the circulation desk of a public library.

A beautiful multicolored mound formed by the mineral deposits of the Orenda Spring.

The first evidence of some of the Earth's earliest life was found in this fossilized undersea grotto.

One of Canada's tiniest museums tackles the world's largest turtle.