The building's tower was illuminated with blue, red, yellow and green - the flag of South Africa.
Mandela, who had spent 27 years in South African prisons for opposing apartheid, passed away at the age of 95.
His death is being mourned across the world with global leaders paying homage to his life-long fight against racial oppression.
The United Nations flags were also lowered at the UN headquarters in memory of Mandela.