Called “Blue Gold”.. indigo..

.. had a high trading value into the 19th century around the world.  There were many conflicts and misuse of indigenous people used to plant, cultivate, and process indigo in many places such as Bengal, and India, but the demand for the dye continued to climb.  In 1897, 998 square miles were dedicated to its growth in India  – about 2 times the size of New York City.

(Photo: dying indigo in Miao)