Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

These pretty kitties killed and ate as many as 135 railway workers.

Landmark Chicago building narrowly avoided destruction.

Huge abstract sculptures of the Puerto Rican Flag.

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

The final resting place of the world's first nuclear reactor.