Rome's Colosseum is one of the most recognizable structures on the planet, but few travelers know that a beautifully preserved Roman amphitheater still stands on the coast of Croatia. The Pula Arena was built in the first century, around the same period as the Colosseum, and it once seated more than 20,000 spectators for gladiator contests.

What makes Pula so special is how complete it remains. It is the only surviving Roman amphitheater to keep all four of its side towers along with its three classical architectural orders. Better still, it is still very much in use. On summer evenings the ancient stone fills up again, this time for concerts, film festivals and opera under the stars.

These two French Gothic cathedrals look remarkably alike, and there is a good reason for that. Both belong to the great age of French cathedral building, with soaring stone arches, rose windows and elaborate carved facades. Notre-Dame owes much of its worldwide fame to Victor Hugo, whose 1831 novel, later known in English as The Hunchback of Notre-Dame, followed the bell ringer Quasimodo and a young Roma dancer named Esmeralda. The book helped inspire a major restoration of the cathedral.

About an hour and a half north of Paris, Amiens Cathedral quietly outdoes its famous cousin in sheer scale. It is the largest cathedral in France by interior volume, tall enough to hold Notre-Dame twice over, and its west front is covered in some of the finest medieval sculpture in Europe. Best of all, you can usually admire it without the long lines and dense crowds.
 

Machu Picchu is the most famous Inca site in the world, and visiting it has become an expensive, tightly managed affair. Tickets are limited, the trek can be exhausting, and the crowds are constant. For travelers who want Inca history in a calmer setting, Bolivia offers a wonderful alternative.

Isla del Sol, the Island of the Sun, sits in the deep blue waters of Lake Titicaca, the highest navigable lake on earth. In Inca legend this island was the birthplace of the sun itself. Scattered across its hillsides are ancient stone ruins, terraced gardens and old pilgrimage paths, all linked by foottrails with sweeping views of the water and the snowcapped Andes beyond. There are no cars here, only quiet villages and centuries of history.
 

Stonehenge draws millions of visitors, yet many leave a little disappointed. You cannot walk among the stones or touch them, there is little shelter if the weather turns, and admission is far from cheap. Just a short drive north lies a prehistoric wonder that asks for none of that.

Avebury is the largest stone circle in the world, so vast that an entire village sits comfortably inside it. Here you can wander freely among the ancient standing stones, rest your hand on them and picnic in their shadow, all completely free of charge. It is older, larger and far more peaceful than its famous neighbor, and both sites are part of the same UNESCO World Heritage listing.
 

Petra, the rose colored city carved into the cliffs of Jordan, feels like something out of a fairy tale. In recent years, though, heavy tourism and modern development around the site have taken a little of the magic away. For an equally spellbinding experience off the usual trail, look to Ethiopia.

Lalibela is home to eleven medieval churches, not built up from the ground but carved straight down into solid rock more than 800 years ago. The most astonishing of them is the Church of Saint George, cut in the perfect shape of a cross and sunk deep into the earth. Still an active place of worship and pilgrimage, Lalibela offers the same sense of awe as Petra, with a fraction of the crowds.

Angkor Wat in Cambodia is one of the great temple complexes of the world. It was built in the early twelfth century as a Hindu temple honoring the god Vishnu, and only later became a place of Buddhist worship. Today it is anything but forgotten, welcoming huge numbers of visitors who come to watch the sunrise behind its famous towers.

For a similar sense of ancient grandeur with far more breathing room, travel to the island of Java in Indonesia. Borobudur is the largest Buddhist temple on earth, built in the ninth century as a vast stone mountain of terraces and domes decorated with thousands of relief carvings and hundreds of serene Buddha statues. Climbing its levels at dawn, with mist rising over the surrounding volcanoes, is an unforgettable experience.
 

With its swirl of brightly painted onion domes, Saint Basil's Cathedral on Moscow's Red Square is one of the most instantly recognizable buildings in Russia. Fewer travelers know that a second, equally dazzling church stands in Saint Petersburg, clearly inspired by the Moscow original.

The Church of the Savior on Spilled Blood was built on the spot where Tsar Alexander II was fatally wounded in 1881, and it took more than two decades to complete. Its colorful domes and richly patterned exterior echo Saint Basil's, while inside it holds one of the largest collections of mosaics in the world, covering nearly every surface in shimmering detail.
 

Ancient columns and marble temples are so linked with Greece that most travelers head straight for the Acropolis in Athens. Just across the Aegean, though, Turkey holds one of the best preserved classical cities anywhere.

Ephesus was once a thriving Greek and Roman metropolis. Walking its marble streets, you pass the beautifully reconstructed facade of the Library of Celsus and a grand open air theater that could hold around 25,000 people. Nearby once stood the Temple of Artemis, one of the Seven Wonders of the Ancient World. Ephesus may not have the Acropolis fame, but it lets you step into a complete ancient city rather than admire a single hilltop.
 

The Golden Gate Bridge in San Francisco is one of the most photographed structures in the world, with its towering orange towers rising above the bay. Travelers are often surprised to learn that a strikingly similar bridge stands in Europe.

Lisbon's 25 de Abril Bridge spans the Tagus River and looks so much like its California cousin that first time visitors do a double take. The resemblance is no accident, since it was built by the same American company behind San Francisco's Bay Bridge. Its reddish orange steelwork, long suspension span and busy waterfront setting make it a wonderful stand in for the Golden Gate, without the transatlantic flight.

London's famous clock tower, the one most people call Big Ben, is a symbol of Britain the world over. What many do not realize is that Canada has a grand version of its own. On Parliament Hill in Ottawa rises the Peace Tower, a soaring neo Gothic tower with a huge clock face and a carillon of bells, completed in the 1920s as part of the country's parliament buildings.

Set above the Ottawa River, the tower makes a stately centerpiece for the capital. As a small note of trivia, the name Big Ben actually refers to the great bell inside the London tower rather than the tower itself, which is officially the Elizabeth Tower. Ottawa's Peace Tower offers the same romantic silhouette, and you can often enjoy it in a far more relaxed setting.