A World of Circles

A ring-shaped lake floods the remnants of a crater formed some 214 million years ago by a meteor impact. A 1960s-era dam, located south of the crater, formed the lake. The impoundment is part of the giant complex of hydroelectric facilities that provide power to Canadian cities.

Developer Dell Webb opened Sun City in 1960 as a pioneering planned retirement community. It is home to 37,000 seniors, who enjoy its golf courses, recreation centers, and other amenities.

Part of a sprawling government complex under construction in the desert east of Cairo, the "Octagon" outdoes the U.S. military headquarters, the Pentagon, not only in terms of number of sides, but also in total floor area among its ten octagonal structures.

Groundwater is pumped to the surface and sprayed on fields using a rotating mechanism. Thousands of these features dot the western Great Plains.

The campus of "UVic" is dominated by a Ring Road, which is almost 2,000 feet in diameter. The campus was formerly nestled entirely within its ring, but has grown beyond its confines.

Traffic swirls around Paris's Arc de Triomphe. A dozen streets radiate outward from the circle, including the famous Avenue des Champs-Élysées, which angles from upper left to lower right.

The Maya Devi Temple nestles at the physical center of a circular sacred garden—and at the spiritual center of Buddhism. It is traditionally considered the site of the birth, in 623 BCE, of Siddhartha Gautama, who was to become Buddhism's founder.

Also called the Richat Structure, this nearly circular West African formation is not a meteor crater. It's an eroded geologic dome.

This circular earthen structure was built by the Hopewell culture between 250 and 500 CE. It is one of three earthworks protected within the Newark Earthworks State Park.

Australia's Parliament House resides within a rectangle within a circle within a larger circle. The city was designed by American architect Walter Burley Griffin, who clearly had a penchant for geometric shapes linked by grand axes.

The radio telescope is 1,000 feet in diameter. It was built in the 1960s above a natural depression and was long used by the Search for Extraterrestrial Intelligence (SETI) project. The dish had been slated for decommissioning when it collapsed in December, 2020.

This circular, high-speed test track in southern Italy was acquired by Porsche in 1975. Its roadsters complete a lap every 7.8 miles.

About 50,000 years ago a meteor 160 feet across paid a visit to what is now northern Arizona, leaving this divot, the diameter of which is about three quarters of a mile.

Kattenbroek is a suburb of the city of Amersfoort. Much of the low-lying landscape of Holland is meticulously planned and densely populated.

The Tevatron is a particle accelerator at the Fermi National Accelerator Laboratory outside of Chicago. It has been inactive since 2011, but is famed among physicists as the site of the discovery of the top quark in 1997.

The Stone Age ruin outside of Salisbury is at least 4,000 years old, and is the largest and most famous of hundreds of stone circles that dot the British Isles.

A circular sinkhole punctuates Lighthouse Reef about 45 miles offshore from Belize City. The hole is a popular diving site.