LONDON (Reuters) - Pieces of a 130-tonne “fatberg”, a ball of fat and waste that was discovered in a London sewer in late 2017, have gone on display at a museum in the city.

The sections of the fatberg, the largest of which is roughly the size of a shoebox, go on display today in the Museum of London, contained inside specially constructed display cases in order to conserve them, and to protect visitors from their more unpleasant side effects.

“It is hatching flies,” Vyki Sparkes, curator at the Museum of London told Reuters of the largest fatberg piece. “There were about two or three seen yesterday, dancing on the surface, but they are fully enclosed and there’s no risk to the public.”

The fatberg from which the specimens came was found in a Victorian-era sewer in Whitechapel in September 2017. Authorities said that the mass of wet wipes, nappies, fat and oil was one of the largest they had ever encountered.

It was as long as three football pitches and weighed as much as 11 double-decker busses.

The exhibition also showcases the work that went in to clearing the fatberg, which involved a crew using jet hoses to break up the mass before sucking it out with a tanker. It took nine weeks.

The exhibition runs from Feb. 9 to July 1 and is free to visit.