Super heroes, princesses and wild animals were all part of a special event at ZooMontana Saturday.

The annual Boo at the Zoo attracted thousands of people and their little ones. People young and old were dressed up for the event and trick-or-treated around the zoo.

Many young kids sported animal costumes, but other popular costumes included sports figures or movie super heroes.

"I think they like it because for one, it's a free day for kids and they get to dress up in costumes. It's a safe place to come trick-or-treating and it's in the middle of the day too, so you're not freezing cold at night. And then two, we have a bunch of animal enrichments going on, so it's a really fun way to spend a day at the zoo," ZooMontana Director Jackie Worstell said.

ZooMontana officials say the event ends at six pm and they expect about 5,000 people to attend this year's Boo at the Zoo.