I have watched(on TV) that the spending on Taj Mahal was so huge that it brought misery to the kingdom.
So how much did Shah Jahan actually spend?(in whichever monetary unit you think is appropriate).
Aboutcivil.org estimates the value at 50 million rupees based on the price of gold to rupees at the time. The site estimates the value at $500 million in 2005. At 1.4 rupees per gram of gold, that's around 35,700 kilograms of gold. Today that's worth around $1.5 billion. Certainly enough to put a dent in almost any treasury.