In 1942, during the 2nd World War, the British thought that the Taj Mahal was vulnerable to bombing by the German Luftwaffe bombers (and also the Japanese) and placed bamboo scaffolding over the Taj Mahal.
While the images here only show the dome of Taj Mahal covered with a thick layering of bamboo scaffolds, it is widely believed that the whole Taj Mahal was layered.
The same thing was done when India was fighting a war against Pakistan in 1965 and 1971.
The purpose of the scaffolding was to make Taj Mahal look like nothing but a bamboo stockpile from inside of a bomber plane flying miles above.
Keep in mind that back then there was no high precision GPS, and satellite imagery.Another thing that is hardly known is that Taj Mahal was covered with cloth after the 9/11 attacks on the world trade towers as a precautionary measure by the Archeological Survey of India.