I still wonder how stone was carved into statues, columns and other things hundreds of years ago.
Marble is fairly soft as rocks go.................
By skilled craftsmen with a hammer and chisel. Specifically it was a technique the Indians had learned from the Italians called "pietra dura," Italian for "hard rocks."
The Italians have been trading with the Indians since the reign of Caesar Augustus. That's why the Italians had Asian buffalo from which to make bufala mozzarella, one of the key ingredients in pizza. And how the Indians came to know pietra dura.
Agra today is full of crafts shops where they make jewelry and home decor by the same technique. Just a man, usually sitting cross-legged in the floor, with a mallet, a bunch of chisels and pieces of marble, some gemstones and a buffing wheel. First he carves out the indentation in the larger piece, purely by eye and feel, then he shapes the gemstone inlay and polishes it until it fits perfectly.
And every shop you go into they'll tell you their craftsmen are the direct descendants of the men who built the Taj Mahal. But it took tens of thousands to build, so 400 years later, it's not impossible that everybody in town is kin to someone who worked on it.
Parts of the Taj today look pretty grim. Lots of the gemstone inlays are gone, leaving just a scar in the marble. And industrial pollution (India has no pollution laws to speak of, and the ones that exist aren't enforced vigorously or uniformly) hasn't been kind to the structure. It's a mausoleum built by the Mughal emperor Shah Jahan for the most beloved of his wives, Mumtaz. "Taj" is Urdu for "crown" but the name also might be an abbreviation or corruption of "Mumtaz."
Once the Taj was done the Shah intended creating its black twin on the opposite bank of the river to be his own mausoleum, but he died before it ever began in earnest. So he in entombed in the Taj, next to Mumtaz.