Somewhere outside Sarajevo, Bosnia, looming over a small town called Visoko, sits the mysterious Visocica hill, which renegade researchers now claim to be a man-made structure: a pyramid estimated to be 235m high, one-third taller than the Great Pyramid of Giza in Egypt.

While experts say there is no scientific basis for his claims, 45-year-old Semir Osmanagic, an amateur Bosnia archeologist who has spent the last 15 years studying the pyramids of Latin America - is convinced that sitting underneath the hill is a giant step pyramid.

Many of the ancient pyramids of Egypt used to be plated in gold and polished white limestone to reflect and amplify the rays of the sun. Now a modern pyramid is being built in India covered in glittering solar panels that similarly pays tribute to the sun. The Singapore-based MSC Power Corp has designed its solar pyramid as a next-gen electricity plant that generates up to 36 megawatts – enough to power towns in rural India that currently have no access to the grid. It also has a desalination component that removes salt from seawater to make it potable.