Secrets of Ancient Structures - Season 1 Episode 4 -

Humanity's relentless drive to innovate has left an indelible mark on our planet's most volatile landscapes. Atop the sheer volcanic plug known as Sigiriya, a Sri Lankan King builds an impregnable fortress, complete with innovative hydraulics and stunning frescoes. On Easter Island, the resilient Rapa Nui people carve and transport colossal moai statues, their cultural practices enduring beyond European contact. And in India, the Kailasa temple at Ellora stands as an architectural marvel. Inspired by the legend of a queen's vow, the miraculous structure is carved top-down from solid basaltic rock.