Ever wonder how some of these ruins last so long?
(Y.Shishido/Wikimedia Commons via archaeology.org)
In some cases, such as India’s Ellora Caves, they’re built using hempcrete, a mixture of hemp and plaster. From another article, this one not yet online but in Archaeology (July/August 2016, p 25):
They’ve survived more than 1,500 years in part, the authors of a new study believe, because hemp – cannabis, known as bhang in India – was mixed with the plaster. The composite material, called hempcrete, can provide strength, thermal insulation, fire resistance, pest resistance, and sound absorption.
Here is a link to a modern version of hempcrete.
