20,000 Trick Or Treaters take over Cheyenne Mountain for annual Boo at the Zoo in Colorado Springs

— The popular Boo at the Zoo event returns to the Cheyenne Mountain Zoo. With the cool down we are talking about, make sure you bundle those kids up.

It sells out often and is expected to sell out this year as well. Now if you do go, you may want to bring something to bring home candy. Organizers say they have 4.5 tons of candy- or as they put it, an "elephant-sized amount" of candy will be given out!

Every year, the entire zoo is covered with Halloween decorations. This year, there's a pirates' cove, a spooky graveyard, a pumpkin patch, and a haunted house. There are also several animal demonstrations with lions, wallabies, and hippos. (oh my!)

We talked with Rachel Wright, the spokeswoman at the Cheyenne Mountain Zoo. She tells us events like this are crucial to their everyday operations. "Boo at the Zoo is one of our biggest fundraisers of the year- we are one of the only AZA-accredited zoos that don't receive tax support so the special events are really crucial and helping us continue to fund animal care, zoo, improvements, operations, and conservation."

Besides wearing warm clothes, you also need to know that no masks or weapons are allowed with your costume. There are a lot of great spots for pictures out here. Like I said, tickets do sell out, so if you want tickets, just head over to the zoo's website .