How many bricks are there in the Great Wall of China?

Question

I am looking for the historical facts about the TajMahal i.e.

1. Who built TajMahal?
2. When was it built?
3. Who was its chief architect?
4. How many years it took to complete it?
5. How much was spent on building it?
6. How many workers has worked to complete it and are they slave?
7. And most important why was it been built?

Answer 1

According to the following site, the famous Great Wall of China, constructed around 210 BC, is made of 3,873,000,000 individual bricks. but some so sites said we cant say its accurate.