The US-based Smithsonian Institution is looking to raise US$1.5bn (€1.2bn, £928m) in an organisation-wide fundraising campaign – the largest in history for a cultural body.

A ‘quiet’ phase of the campaign has been ongoing since October 2010, with the campaign due to continue through to 2017. So far, the Smithsonian says it has raised two thirds of its target, accruing US$1bn (€781m, £619m) over the past four years through gifts from individuals, foundations, corporations and other donors.

The campaign is focusing its efforts on the institutions focus on history, science, art and culture using the messages ‘Spark Discovery’, ‘Tell America’s Story’, ‘Inspire Lifelong Learning’ and ‘Reach People Everywhere’.

The main complex in Washington D.C. still needs about US$100m (€78.2m, £61.9m) a year for maintenance, but federal funding has fallen below that sum. Since its founding in 1846, the Smithsonian has been supported by public and private finance. It has historically received federal taxpayer funding for about 70 per cent of its annual budget for both staff salaries and building maintenance, but that amount has recently declined to around 60 per cent.

The US$1.5bn sum is a joint effort between the Smithsonian complex in Washington D.C. as well as the 19 other museums in Washington and New York City, the National Zoo (also in Washington) and nine research facilities around the world.

Among the funding already raised, David H. Koch donated US$35m (€27.3m, £21.6m) for a large-scale renovation of the Smithsonian's dinosaur hall. Boeing has donated US$30m (€23.4m, £18.5m) to overhaul the central exhibition showing the milestones of flight at the National Air and Space Museum. Television presenter Oprah Winfrey also notably donated US$13m (€10.1m, £8m) to build a new National Museum of African American History and Culture.

“The level of excellence expressed in the Smithsonian’s strategic plan can be achieved only with a significant infusion of philanthropic capital,” said David Rubenstein, co-chair of the campaign’s steering committee. “The Smithsonian Campaign is providing this, funding the plan’s vision and the big ideas in it – ideas that are transforming the Smithsonian’s future.”

Washington D.C. was recently named by Lonely Planet as the best city to visit in 2015, with one of the main reasons for this being its housing of the bulk of the Smithsonian Institution.