The Detroit Zoo is luring visitors with the temptation of a free bucket of animal poop.

On Saturday, April 14, the zoo will host its sixth annual GreenFest, an event dedicated to celebrating Earth Day and engaging the community.

So how do you get your free poop?

The first 1,000 people to visit the anaerobic digester educational display will receive a token for a five-gallon bucket to be filled with free Detroit Zoo poo.

The anaerobic digester annually converts 500 tons of animal manure and other organic waste into methane-rich gas to help power the zoo's animal hospital, leaving a nutrient-rich fertilizer as a byproduct.

GreenFest guests can also explore farm-to-table food options, expand their scientific knowledge during chemistry demonstrations, make window decals to prevent bird strikes and take a green pledge to join the Detroit Zoological Society on its Green Journey.

The event runs from 10 a.m. to 3 p.m.