Short answers, pulled from the story.
Emperor Shah Jahan issued a command on the 12th of May 1639 to shift his capital from Agra to Delhi which triggered the construction. Work began in the sacred Islamic month of Muharram on the 13th of May 1638.
The Red Fort spans an area of 254.67 acres enclosed by 2.41 kilometres of defensive walls varying in height from 18 meters to 33 meters. These walls are octagonal with the north-south axis longer than the east-west axis and feature red sandstone adorned with white marble details.
Construction continued for nearly ten years until the fort was completed on the 6th of April 1648. The original design featured red sandstone walls adorned with white marble details.
Following the Indian Rebellion of 1857, British authorities ordered the systematic demolition of the Red Fort. During this process 80% of the fort's structures were destroyed including the stone screen that once connected pavilions along the river-facing façade.
On the 15th of August 1947 Jawaharlal Nehru raised the Indian national flag above the Lahore Gate marking India's first Independence Day. Since then the Prime Minister has ceremonially raised the tricolour at the main gate each year on Independence Day.