AMAZING AND ADVENTUROUS...

1. Eye of Africa, MauritaniaThe 'Eye of Africa' (also known as the Eye of the Sahara) lies within the large east-African country of Mauritania, out in the Sahara Desert. Properly known as the Richat Structure, it is easy to see where its nickname comes from. Looking at it from above, it looks a lot like a big blue eye staring out of the ground.

2. Iron pillar of Delhi, IndiaAn ancient iron pillar in Delhi which seems to be rust proof.The Iron Pillar located in Delhi, India, is a 7 m (23 ft) column in the Qutub complex, notable for the rust-resistant composition of the metals used in its construction. The pillar has attracted the attention of archaeologists and metallurgists as it has withstood corrosion for the last 1600 years, despite harsh weather and has been called "a testament to the skill of ancient Indian blacksmiths" because of its high resistance to corrosion. The iron pillar is one of the world's foremost metallurgical curiosities. The pillar, almost seven metres high and weighing more than six tonnes, was erected by Chandragupta II Vikramaditya (375-414 CE).
The pillar bears an inscription which states that it was erected as a flagstaff in honour of the Hindu god, Vishnu, and in the memory of the Gupta King Chandragupta II (375-413). Made up of 98% wrought iron of pure quality, it is 23 feet 8 inches (7.21 m) high and has a diameter of 16 inches (0.41 m). Also, it was confirmed that the temperatures required to form such kind of pillars cannot be achieved by combustion of coal. The pillar is a testament to the high level of skill achieved by ancient Indian iron smiths in the extraction and processing of iron.

 20 million years ago. Most of the formations are connected to the underlying rock mass. The Yonaguni Monument is a massive underwater rock formation off the coast of Yonaguni, the southernmost of the Ryukyu Islands, in Japan. A local diver first noticed the Yonaguni formations in 1986. There is a debate about whether the site is completely natural, is a natural site that has been modified, or is a human-made artifact. For these reasons, the site is also known in Japanese as the "Yonaguni (Island) Submarine Ruins".

3. Yonaguni Monument, Underwater Ruins, JapanThe Monument consists of medium to very fine s
andstones and mudstones of the Lower Miocene Yaeyama Group believed to have been deposited about

4. Stone Spheres of Costa Rica

The Stone Spheres of Costa Rica are a collection of over 300 almost perfect spherical orbs first discovered in the Diquis Delta in the 1930's. They vary in size from a few centimeter to several meters, the larger stones weigh nearly 16 tonnes. Most are sculpted from granodiorite, an igneous rock similar to granite. They are believed to have been created between 200 BC and 1600 BC. The stones are often grouped together in geometrical patterns, often pointing to magnetic north. Local people call those spheres 'Las Bolas' and they can be found in many parts of Costa Rica.