For the past few years, workers have been slowly giving one of the world’s most famous buildings a much-needed mud bath. When the Taj Mahal was completed 365 years ago in Agra, India, its marble exterior was a brilliant white. But over time, small particles of air pollution around the building turned the stone yellow and black.
To get rid of the grime, workers have been covering sections of the building with highly absorbent clay. As the clay dries, it soaks up the pollutants from the stone. Workers then wash off the dried mud to reveal a restored white surface.