<P> The fort was plundered of its artwork and jewels during Nadir Shah's invasion of the Mughal Empire in 1747 . Most of the fort's precious marble structures were subsequently destroyed by the British following the Revolt of 1857 . The forts's defensive walls were largely spared, and the fortress was subsequently used as a garrison . The Red Fort was also the site where the British put the last Mughal Emperor on trial before exiling him to Rangoon in 1858 . </P> <P> Every year on the Independence day of India (15 August), the Prime Minister hoists the Indian "tricolour flag" at the main gate of the fort and delivers a nationally broadcast speech from its ramparts . </P> <P> It was designated a UNESCO World Heritage Site in 2007 as part of the Red Fort Complex . </P> <P> Its English name, "Red Fort", is a translation of the Hindi / Urdu Lāl Qila deriving from its red - sandstone walls . As the residence of the imperial family, the fort was originally known as the "Blessed Fort" (Qila - i - Mubārak). Agra Fort is also called Lāl Qila' . </P>

When was red fort granted the world heritage site