After a 146-year run, the curtain falls on “The Greatest Show on Earth” with an evening performance at the Nassau Veterans Memorial Coliseum in Uniondale, N.Y.

Ringling Bros. and Barnum & Bailey Circus took a final, bittersweet bow Sunday, staging its last three shows here after 146 years of entertaining American audiences with gravity-defying trapeze stunts, comically clumsy clowns and trained tigers.

“Farewell, from the Greatest Show on Earth!” ringmaster Johnathan Lee Iverson, an 18-year veteran of the show and the first African American to hold the job, told each packed audience, offering one of the few signs that the circus was coming to a close. Yet many spectators said they came precisely because Sunday offered the final chance to witness a spectacle that once felt as if it might be around forever — until changing times and mores proved more powerful.

“It’s sad, but the memory lives on,” said David Eisenberg, a business development manager from Massapequa, N.Y., who first beheld the circus half a century ago with his grandfather. He took his daughter when she was little, and he and Rachel, now 25, returned one more time Sunday night.

“Everybody is a kid at heart,” Eisenberg said.

The end of this American institution came six decades after it folded its big-top tent in 1956 and moved indoors, an event that at the time was viewed as a death knell. But while Ringling’s mile-long train of animals and humans continued crisscrossing the country, it ultimately could not weather another major transition: last year’s exit of its most famed performers, the elephants.

The animals had long been the huge draw, but they were also what contributed to the circus’s demise. In 1898, when Ringling’s “World’s Greatest Show” first made its way to the nation’s capital, some 15,000 people packed into a tent to view what The Washington Post then called “one of the finest zoological exhibits extant.” It included tropical birds, a hippo, zebras, 400 horses and 25 elephants.

A century later, Ringling had become the target of animal protection groups that claimed it mistreated its elephants, and the two sides soon locked in a 14-year legal battle so cutthroat it involved secret informants paid by animal groups and a former CIA official who was paid by Ringling’s parent company, Feld Entertainment, to spy on activists and a journalist. The litigation ended with several animal groups paying a $16 million settlement to Feld.

While the animal activists never prevailed against Ringling in court, they were victorious outside. The allegations of elephant abuse prompted municipalities around the country to ban elephant bullhooks — a sharp metal tool used by handlers — or to prohibit wild animal performances altogether, as Los Angeles recently moved to do. After Ringling retired its last pachyderms to a company-owned elephant conservation center in Florida, ticket sales declined much more than Feld expected, and the company announced in January that Ringling would close for good.

“The legislative landscape . . . made it really difficult to tour with the elephants,” Alana Feld, the company’s executive vice president, said Friday.

Aerialist Paulo dos Santos flies through the air during his act Sunday. (Michael S. Williamson/The Washington Post)

But the circus was also contending with evolving public tastes and an ever-widening entertainment landscape.

In the early to mid-20th century,…