How many years did it take to complete the entire Taj Mahal complex, including its mosque, gateway, and gardens?

Answer

22 years

Around 20,000 artisans worked on it, with materials hauled by a reported fleet of 1,000 elephants. Emperor Shah Jahan built it as a tomb for his wife Mumtaz Mahal — and ended up imprisoned by his own son, gazing at it from a fort across the river.

Source: UNESCO World Heritage Centre / Encyclopaedia Britannica