San Francisco — Thirty years ago, hundreds of smelly, noisy sea lions invaded the boat docks of Pier 39 on San Francisco's Fisherman's Wharf. Sheila Chandor had just started her job as harbormaster back then.

"If you can imagine 1,400 animals on that dock. It was just a seething mass of sea lion noise... and smell," Chandor said.

But the blubbery marine mammals have become an unlikely tourist attraction. Chandor estimates "millions" of people have come to see the sea lions over the years.

In appreciation for bringing in all those tourists, San Francisco is celebrating the sea lions with 30 colorful sculptures going up around town, along with a proclamation by Mayor London Breed, announcing January 16th as "Sea Lion Day." It's a lot of excitement over an animal that spends much of its time just lying in the sun.

Tourists watch sea lions at San Francisco's Pier 39. Getty

"I want some entertainment from them and they've got nothing," one tourist said.

It is perhaps a part of their appeal, the sea lions are free to come and go but they have kept coming back for three decades. Chandor admits they worry the sea lions will one day decide to go somewhere else, "but we don't speak about that."