One of the first public landmarks to be transformed was the eight-lane I-35W Mississippi River bridge in his home town of Minneapolis.
The Minnesota Department of Transport said that the bridge and the city's famous Lowry Avenue Bridge over the Mississippi river had been illuminated in the colour of Prince as the state mourned with the world over the loss of a "true artist and a beloved Minnesota son".
Similar purple tributes to the star were made in Washington DC, New York and Los Angeles.
The Niagara Falls also turned purple - initially regal purple to honour the Queen's 90th birthday - but in a strange twist it also became an official tribute to the dead star, Canada's Toronto Sun reported.
Twitter users reported that the Eiffel Tower in France had turned purple while the Ritzy cinema in south London carried lines from one of his hits: "This is what it sounds like when doves cry."
A weather forecast sign in Sydney, Australia, read "cloudy with a chance of purple rain".
Key landmarks across the US have turned purple in honour of the singer and superstar Prince, who was found dead at his Minnesota home on Thursday.