This site is home to ancient petroglyphs and pictographs dating back to 6,000 B.C.

It's safe—and permitted—to walk across these twin natural sandstone arches.

This raised bulls-eye visible from space was the subject of an intense geologic controversy.

A small oasis not far from downtown Moab.

This Moab institution functions as both a rock store and a small natural history museum.

A crack flared at the base provides a pathway completely through a sandstone ridge near Moab.

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

Around half a million years ago, these magnificent columnar basalt cliffs were formed from cooling lava.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

An architect's childhood fantasy treehouse made real.

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

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

G.V. Black, the Father of Modern Dentistry, keeps an eternal eye on Chicagoan’s teeth from his perch in Lincoln Park.

A journey begins with a single step, and for many, the road-trip of a lifetime started at this Chicago intersection.

The last masonry skyscraper ever built reveals a transitional moment in architectural history.

A 19th-century horse lover's bequest led to the construction of this unique fountain in Chicago.

These chunky stone towers out in Lake Michigan are the key to Chicago’s drinking water.

This abstract sculpture is rumored to cast a hammer-and-sickle shadow once a year.

A spectacular remnant of an Adler and Sullivan masterpiece that was destroyed in 1972.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

A goddess-topped water fountain in Chicago was created thanks to the dreams of a thirsty newsboy.

A Japanese temple, old German townhouses, and public chess tables offer a peaceful escape from the bustle of the North Side.