Hear the quietest sound from across the dome.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Northern Ireland's Brobdingnagian stepping stones.

The ancient tomb acts as a calendar that keeps perfect time.

Mysterious 500-year-old tapestries depict a unicorn hunt.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Visit the monolithic tomb of America's most famous general.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

A Natural History and Science Emporium.

A self-made museum in Queens, New York continues to display the work of a sculptor known for paving his own way.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

On this island, you suck away your garbage via an elaborate pneumatic tube system.

A crumbling hospital from the 1850s on Roosevelt Island.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elevated freight railway turned wildly successful urban park.

Lie in a hammock where George Washington stood.

An artist's cute bronze subway sculptures belie his violent artistic past.

Ride the subways of yesteryear.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

The most confusing clock in New York.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

See massive fossils that are over 200 million years old in northeastern Arizona.