1. Gobekli Tepe
Back in the 1960s, surveyors in Turkey found an ancient buried complex composed of huge stone pillars arranged in a circle like Stonehenge, some of them 30 feet tall.
So those massive, ornate limestone pillars were carefully carved from a nearby quarry using hunks of flint rock and their bare hands.
Having been dated to around 9000 B.C., Gobekli Tepe is thought to be the oldest human construction.
2. Puma Punku
Pumapunku is a city built by the Tiwanaku people of ancient Bolivia. What sets it apart from just any old ancient city is the almost weird precision of the stonework that would make modern builders envious.
Using an unknown technology, they pioneered a kind of construction that used hundreds of large, identical building blocks to make buildings like you and I would make a house out of LEGO.
To keep the buildings structurally sound, they even used a form of metal I-cramps similar to what we would use today to keep the giant blocks in place in case of an earthquake.
3. The Ancient Marib Dam
Yemen is a country rich in dust and poor in water, which is why in ancient times the empire that controlled it, the Sabaens, built a great dam in 750 B.C.
The dam was regarded one of the greatest feats of engineering of the pre-industrial age. The Sabaens managed all this before the existence of concrete, and their dam stood for over 1,000 years.
The Great Dam of Marib was about 2,000 feet long and while it stood, it converted ancient Yemen into a fertile oasis.
4. Hypogeum of Hal-Saflieni
On the island of Malta is a prehistoric underground megalithic structure known awesomely as the Hypogeum of Hal-Saflieni. It was discovered by accident in 1902 when some workers were digging a hole and broke through the ceiling.
The three-level underground structure is made entirely out of megalithic stones. What surprised people even more was when they found out that male voice could reverberate throughout the entire complex if the person was standing in a certain spot.
5. Derinkuyu’s Massive, Ancient Underground City
Derinkuyu’s underground city was discovered in the 1960s in Turkey, when a modern house above ground was being renovated.
Hidden for centuries right under everyone’s noses, Derinkuyu is just the largest of hundreds of underground complexes built.