
(1) Great Wall, Badaling, China
By their very purpose, walls protect, but also acknowledge limits, physical and otherwise. The sheer size and scope of this structure (8,850 kilometres), built by millions of slaves across centuries, makes the Great Wall a subject worthy of our study.
(2) Colosseum, Rome, Italy
An iconic symbol of Imperial Rome, this amphitheatre could hold anywhere between 50,000 and 60,000 spectators following its completion in AD 80. The days of panem et circenses are long gone, but the Colosseum — despite the damage it has endured through the ages — remains a concrete tribute to the engineering skills of its builders.

(3) Pyramids of Giza and the Great Sphinx, Egypt
We know that the Great Pyramids of Giza served as tombs for a trio of ancient Egyptian pharaohs, one of whom supposedly constructed the nearby Great Sphinx, a mythical creature that is part lion, part human. We also know that this complex is the oldest and only survivor of the ancient Seven Wonders of the World, as described by the Greek historian Herodotus. Many of the questions they raise remain unresolved and as such, they force us to contemplate the eternal.

(4) Acropolis of Athens, Athens, Greece
The flags of countless invaders have flown over Athens’ Acropolis, an archeological jumble of temple sites with the Parthenon as its centrepiece. Dedicated to Athena, the Greek goddess whose name the city bears, the temple stands for the defiant spirit of Athens and its people through the ages of history.
(5) Chichen Itza, Mexico
Located at the edge of the Yucatan Peninsula, this former Mayan metropolis speaks to the Mayan belief in the cyclical nature of time. Long past its peak when the Spanish conquered the region in the 1520s and 1530s, the city disappeared behind a veil of vines, only to re-emerge in the early 20th Century. At its centre stands El Castillo, or the Temple of Kukulan, a Mesoamerican step pyramid.

(6) Stonehenge, Amesbury, United Kingdom
A source of countless cultural references and an equally large number of esoteric theories about its creators and functions, Stonehenge may never reveal its secrets. What purpose(s) did the circle of large stones serve? Who were the people who build them? Which building methods were used? No matter. It is already an early triumph of human ingenuity and artistry, a neolithic search for the sublime.
(7) Machu Picchu, Peru
A memorial composed of stone and sky, Machu Picchu mourns the ancient Incan civilization. Situated at an altitude of 2,430 metres, scholars consider Machu Picchu one of the most important cultural landmarks in Latin America. The site also serves as a preserve for several endangered animals, their existence as fragile and tenuous as the jungle trails that lead to this fleeting city in the clouds.

(8) Angkor Wat, Cambodia
The centrepiece of a larger archeological complex featuring remains of various administrative and religious buildings, Angkor Wat (Temple City) symbolizes the fusion of religion and politics that powered the former Khmer Empire from the 9th Century until its demise in the 15th Century. This symbiosis has remained visible to this very day. The flag of modern-day Cambodia features a relief of Angkor Wat. As such, the site is a symbol of national pride.

(9) Petra, Jordan
It is “a rose-red city half as old as time,” to borrow a line from English poet John William Burgon. Petra has a powerful, hypnotic effect on visitors as they gaze upon its rock-cut architecture. The prosperous capital of the ancient Nabateans, Petra “fell off” the map for more than a millennium before its “rediscovery” in 1812 and subsequent starring role in the Indiana Jones trilogy.
(10) Gaochang, Xinjiang, China
For daring travellers who wish to experience the ancient Silk Road, Gaochang may be well worth the effort. Located at the edge of the inhospitable Taklamakan Desert, it was once a prosperous stop, with relatively well-preserved ruins to prove it.