SeaWorld is celebrating 30 years in San Antonio with a new "nighttime spectacular" and a big discount.

The park opened on April 15, 1988. People started lining up at 4 a.m. that day to be the first guests inside, according to San Antonio Express-News archives.

To celebrate the anniversary, the park is hosting a flash sale, it announced in a news release Tuesday afternoon. Single-day tickets are $30 — a savings of more than 50 percent. The park is also offering $50 flex tickets, which allows visitors to visit SeaWorld and Acquatica for three consecutive days, as well as $70 annual silver passes and $80 annual gold passes. More discounts for dining and group admission can be found on SeaWorld's website.

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Prices are normally $69 for a single-day ticket, $79 for a flex ticket, $79 for a silver pass and $109 for a gold pass.

The flash sale lasts until July 23. The ticket is valid until Sept. 3, 2018, according to the park's website.

In addition, SeaWorld is celebrating the start of it's all-new nighttime celebration, Electric Ocean. Through Aug. 12, the park converts to a dance club, complete with fireworks shows and a "party zones" with electric dance music.

According to San Antonio Express-News archives, the park was originally planned as an underwater restaurant. It's now one of three SeaWorld locations in the country and is the "world's largest marine life park," with 416 acres, according to the website.

See what the opening day looked like in the gallery above.

Madalyn Mendoza is a digital reporter for mySA.com. Read more of her stories here.| mmendoza@mysa.com | Twitter: @MaddySkye