Neolithic stone circle and henge at Avebury, UNESCO World Heritage Site, Wiltshire, England, United Kingdom, Europe

View of the Acropolis of Athens from Mouseion Hill, located to the southwest. The Acropolis, an ancient citadel perched on a rocky outcrop above the city, contains the remains of several significant ancient buildings, including the Parthenon.

View of Goree Island, UNESCO World Heritage Site, just offshore from, but considered a part of Dakar, Senegal, West Africa, Africa

View of the Acropolis of Athens from Mouseion Hill, located to the southwest. The Acropolis, an ancient citadel perched on a rocky outcrop above the city, contains the remains of several significant ancient buildings, including the Parthenon.

View of the Acropolis of Athens from Mouseion Hill, located to the southwest. The Acropolis, an ancient citadel perched on a rocky outcrop above the city, contains the remains of several significant ancient buildings, including the Parthenon.

View of the Acropolis of Athens from Mouseion Hill, located to the southwest. The Acropolis, an ancient citadel perched on a rocky outcrop above the city, contains the remains of several significant ancient buildings, including the Parthenon.

View of the Acropolis of Athens from Mouseion Hill, located to the southwest. The Acropolis, an ancient citadel perched on a rocky outcrop above the city, contains the remains of several significant ancient buildings, including the Parthenon.

View of the Acropolis of Athens from Mouseion Hill, located to the southwest. The Acropolis, an ancient citadel perched on a rocky outcrop above the city, contains the remains of several significant ancient buildings, including the Parthenon.

Footprints of large plant-eating Jurassic Saurapod dinosaurs, an important middle Jurassic find on the north east coast in 2018, Brothers' Point (Rubha nam Brathairean), Trotternish Peninsula, Skye, Inner Hebrides, Scotland, United Kingdom, Europe

Courtyard of the Black Eunuchs, The Harem, Topkapi Palace,UNESCO World Heritage Site, Istanbul, Turkey, Europe

Aerial of the Guimaraes Castle, UNESCO World Heritage Site, Guimaraes, Norte, Portugal, Europe

Bas Relief of Boats, Tomb of Seti I, KV17, Valley of the Kings, Ancient Thebes, UNESCO World Heritage Site, Luxor, Egypt, North Africa, Africa

View of 42nd Street, a significant crosstown avenue, from the Tudor City Overpass (Tudor City Btidge), Manhattan borough of New York City, United States of America, North America

View of 42nd Street, a significant crosstown avenue, from the Tudor City Overpass (Tudor City Btidge), Manhattan borough of New York City, United States of America, North America

View of Piazza San Carlo, a significant square showcasing Baroque architecture and featuring the 1838 Equestrian monument of Emmanuel Philibert by Carlo Marochetti at its center, Turin, Piedmont, Italy, Europe

View of Piazza San Carlo, a significant city square showcasing Baroque architecture, featuring the 1838 Equestrian monument of Emmanuel Philibert by Carlo Marochetti at its center, Turin, Piedmont, Italy, Europe

Myocardial infarction with a significant thrombus

Temple of Apollo in the ancient city of Didyma, significant sanctuary and Oracle, Turkey

Temple of Apollo in the ancient city of Didyma, significant sanctuary and Oracle, Turkey

Unesco World Heritage Site Monte Alban, Oaxaca, Mexico, Central America, Large stone column in a natural setting under a clear sky, historically significant, Mitla, Central America

Padrao dos Descobrimentos, monument to discoverers, sculpture with significant figures of Portuguese seafaring at the riverside of Tejo, Belem, Lisbon, Portugal, Europe

A sign telling hikers to stay on the trail in Haleakala crater. Hiking off-trail leads to significant soil erosion in the delicate volcanic soils, Maui, Hawaii, United States of America