Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

A walk through the historic city center, under the streets of Seattle.

An extraordinary natural landscape of mountains, waterfalls, and rocky cliffs riddled with tunnels.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

Tijuana's legendary jai alai or "basque ball" palace is now a massive music venue.

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

A display of magnificent stained glass windows is the first exhibit of its kind.

This historic hotel invented the chocolate brownie.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

An enormous park-like oasis, full of famous Chicagoans' graves.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A tall karst islet popularized by 007.

This magnificent Cincinnati graveyard is also a popular public park.

This replica of the Greek structure is in the heart of Nashville.

The "Jade Museum" is full of thousands of intricately carved works of art made from various precious stones.

Mass graves and Victorian monuments mark the history of Memphis in this 19th century cemetery.

Elvis's own personal tropical hideaway.