The instrument was used by the Nirvana frontman in his 1993 MTV Unplugged set, one of Cobain's last appearances before he died.
The work, made with 330 Rubik's Cubes, is by the French artist Invader.
This year, an 18.02-carat diamond ring sold for a whopping £881,250.
An announcement taped to the shopfront said that Banksy will be selling artworks online from as little as £10.
The classic Aston Martin DB5 driven by James Bond in the film Goldfinger has been auctioned in California for 5.77m euros
The bust of the ancient Egyptian boy king was sold at auction on Thursday, despite speculation that it was stolen from a temple in Luxor.
A revolver believed to have been used by Dutch painter Van Gogh to kill himself was sold at an auction on Wednesday.
Franco-Israeli Telecoms magnate Patrick Drahi made a surprise move into the art world, snapping up Sotheby’s in a deal worth 3.27 billion Euros, marking the auction house’s return to private ownership after 31 years
The remains were found in a marsh in Hell Creek Formation in Montana in 2013, according to its owner.