One of the most scenic stretches of road in America winds between some of the country's oldest trees.

The author of Uncle Tom's Cabin was neighbors with Mark Twain while living in this Connecticut home.

Commemorating the spot where the famous scientist fed his pigeons.

Quirky castle designed by the American actor best known for portraying Sherlock Holmes on stage.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

This exhibit allows visitors to wander through the interior of a replica Ice Age glacial cave.

A massive Montreal stadium that has seen nothing but trouble since its inception.

This watchtower once presided over the Berlin Wall.

Berlin's old airport.

The real life town from the Pied Piper of Hamelin has a mechanical puppet show that retells the famous story many times a day.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

This ancient Irish tower could easily have stood in for Rapunzel's prison.

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

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

A tunnel with windows, so you don't miss out on the impressive views.

An architect's childhood fantasy treehouse made real.

The fifth-longest natural arch in the world, and the longest outside China.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."