For centuries, or even millenniums, some of the most astounding sites of ancient times were forgotten or hidden from the world, buried under jungles, deserts, or farmers' fields around the globe. Rumours of lost cities or chance discoveries by people going about their everyday lives have led to unimaginable finds that are today open for the world to see. Many of these have been designated UNESCO World Heritage Sites.

Some incredible sites have been around and attracting tourists for hundreds of years and are as fascinating now as they were when they were first uncovered. It may be a cliché to say there has never been a better time to explore the greatest sites on the planet, but it is also true.

While they're all significant, some are arguably more impressive than others. Below is our list of the best World Heritage Sites.

1. Machu Picchu, Peru

Machu Picchu, Peru

Built in lush, mountainous terrain high above the Urubamba River, Machu Picchu lies in one of the most stunning settings of any archeological site in the world. This ancient city of Incas cascades down steep walls on each side of the mountain, with terraced steps that disappear over cliff edges into the valley below. These incredible ruins have been restored and are well maintained, giving visitors a good indication of what the city might have looked like when it was occupied during the 15th and 16th centuries.

Many people come to Peru for the sole purpose of visiting Machu Picchu, and the journey to the ruins can be an adventure in and of itself, depending on how travelers choose to reach the site. Adventurous souls can opt for a guided, multi-day hike and camping trip along the famous Inca Trail to reach the site, or choose the easier option of accessing the ruins by bus from the small town of Aguas Calientes at the base of the hill, which most visitors get to by train from Cusco or the Sacred Valley.

Accommodation: Where to Stay near Machu Picchu

2. Pyramids of Giza, Egypt

Pyramids, Egypt

One of the most iconic sites in the world, the Pyramids of Giza, just outside Cairo, are a surreal sight rising from the barren desert landscape. Standing guard nearby, and almost as impressive, is the Sphinx, gazing blankly out over the land.

The pyramids were built as tombs for the Pharaohs, the largest of which was constructed between 2560 and 2540 BC. To put their age in perspective, they were already more than 2,600 years old when the Colosseum in Rome was being built. Today, these giant monuments are the sole surviving member of the Seven Wonders of the Ancient World.

Accommodation: Where to Stay in Cairo

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• Pyramids of Giza: Attractions, Tips & Tours

3. Bagan, Myanmar

Bagan, Myanmar

Thousands of ancient temples and stupas stretch endlessly across the landscape at Bagan, where the silhouette of the temple spires against the sky in the early morning or late day is a magical sight. The area is known for having the largest concentration of Buddhist temples in the world, many of which were built in the 1000s and 1100s, when it was the capital of the Pagan Kingdom.

Some of these have been restored, and others are little more than ruins. They also range in size and level of sophistication, creating an intriguing mix of structures that make visitors want to keep exploring the site. You can tour the area on rickety old bicycles, hire a horse and cart, take a hot air balloon ride over the site, or simply hire a taxi. Each of these methods has its own appeal.