Monterey Bay Aquarium in California is celebrating its 40th anniversary this Sunday, Oct. 20, by offering free tickets to Monterey County residents during the month of October.

The free tickets are limited and subject to availability, with a certain number of slots available per day.

Tickets must be reserved online and in advance, with a limit of six tickets per transaction. Photo identification and proof of residency is required for guests 18 and older.

Ticket holders are allowed to enter the aquarium from 12 p.m. to 4 p.m., as opposed to the aquarium’s typical 10 a.m. to 5 p.m. hours.

Monterey Bay Aquarium is a nonprofit aquarium in Monterey with nearly 200 exhibits of animals that are mostly native to the local area.

Famous for its ocean-front view, sea otters, kelp forest, and jellyfish, the popular attraction brings in around 2 million visitors annually from all around the world.

According to its website, the aquarium is a leader in ocean conservation and research and is “transforming what it means to be an aquarium.”

To celebrate the 40-year milestone, the aquarium is also hosting a 40th Anniversary Member and Donor Party on Oct. 19 from 7 to 10 p.m. However, tickets for this event have already sold out.

Additionally, the aquarium is hosting an online event on Oct. 20 at 2 p.m. that includes special guests, games, and a live Q&A.

The following weekend, it is holding two Halloween events at 7 to 10 p.m. on Oct. 26 and 27 for members only.