The glowing blue Nymphaeum of Emperor Tiberius.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A tribute to one granddaughter's old apartment which now represents the whims of each visitor.

World's second largest particle accelerator, where nature reveals its secrets.

The final resting place of two unknown soldiers.

A onetime gangsters' hideaway where you can dine on steaks, fine wines, and cigars just like they once did.

Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.

This house renovated by Frank Lloyd Wright was the centerpiece of a lavish 20th-century estate.

An exhibit of items from the mental institution where Mary Todd Lincoln lived after her son conspired to have her committed.

This architectural stunner is one of the few surviving Egyptian Revival theaters in the U.S.

This unique zoo is the only place in the world where you can see all 15 species of crane.

A remnant of the last Ice Age, this lake is surrounded by fascinating rock formations.

"World's largest scrap metal sculpture" stands in an outdoor sculpture garden in the middle of Wisconsin.

This cave holds a surprisingly colorful variety of geological oddities.

A bizarre house filled with an astounding array of collections.

A lovely hidden waterfall right off the highway is well worth a stop.

The secluded resting place of a local historical figure who perished during the sinking of the Titanic.