The British Museum closed for several hours today as Greenpeace protesters decked out in climbing gear occupied key columns on its façade, unfurling banners on climate change.

The activists were calling attention to the British oil company BP’s sponsorship of the museum’s current “Sunken Cities” exhibition, which the museum is billing as the “first major exhibition of underwater archaeology.” The activists have rebranded it “Sinking Cities.”

The London Telegraph says it’s thought to be the first time the museum has taken such an action.

“BP’s actions around the world are climate-destroying,” says a voiceover in a video on Greenpeace UK’s Facebook page, including, says the videographer, the Deepwater Horizon oil spill in the Gulf of Mexico, “not to mention its continued efforts to find more fossil fuels.”

Fourteen activists affixed the “Sinking Cities” signs to the columns, referring to rising seawater levels that threaten coastal cities worldwide in the era of climate change. The signs include names of threatened locales like Manila, the Maldives, and New Orleans, which was ravaged by flooding during Hurricane Katrina, in 2005.

Photo courtesy Greenpeace UK.

Just yesterday, activists stormed the press preview for “Sunken Cities,” calling attention to environmental damaged caused by the energy company as well as BP’s alliances with repressive Middle Eastern regimes.

Institutions such as the Tate have lost BP sponsorship after numerous protests by arts and environmental groups. BP also ended its support of the Edinburgh International Festival in April after some 34 years.

Greenpeace invites sympathizers to sign a petition calling on the institution to end its sponsorship arrangement with the oil giant. The museum has a five-year contract with the company that is now up for renewal.