After 12 years and 279 episodes, The Big Bang Theory ended with an emotional finale that attracted the biggest audience in recent years.

The one-hour, two-episode finale on May 16 of CBS' longest-running sitcom gathered an audience rating of 3.2 among adults aged 18 to 49 years, the best performance among all scripted broadcast shows this season and the show's highest since January 2018, according to Showbuzz, which tracks movies and TV shows.

More than 18 million viewers watched the final episode, the highest since the show's season 9 premiere in 2015 and the best for an episode of a regular TV series this season.

On Weibo, the Chinese equivalent of Twitter, a social networking site, the tag "Big Bang Theory Finale" got more than 100,000 discussion posts and 200 million views as of Saturday.

Another related tag, "The elevator was fixed in The Big Bang Theory" - the elevator of main characters' apartment that had been out of order since the show's premiere in 2007 but finally worked in the finale - got 160 million views.

Co-created by Chuck Lorre and Bill Prady, it became the most-viewed entertainment show in all of network television.

The show was known for its unprecedented portrayal of scientists as main characters and its affectionate depiction of nerd culture.

The last episode, which many fans called "satisfying" and led to laughters and tears, centered on Sheldon Cooper, a main character played by Jim Parsons, and his wife, Amy, played by Mayim Bialik.

It featured moments, jokes and references that had become the signatures of the show and ended with all the core cast members gathering at the exact place they have always been geologically.

The inclusion of science elements into a sitcom brought the show not only viewers from the US, but a solid international fanbase as well.

"I had never been a big fan of American sitcoms until I watched the first episodes of The Big Bang Theory which was really popular since I was in the middle school," said Shi Qi, 24, a student in the UK, on Weibo.

"It's a relief that the series has come to a perfect end," Sandra Chen, who lives in New York, told China Daily.

"I started following the series since college years. For years, I was thinking how it was going to end. Now I will start rewatching all the 12 seasons."

"Saying goodbye tonight to the show that changed the world for us nerds. That taught us that friendship and love can be found in the most unexpected places," wrote Courtney Duffield on Twitter.

The show had worked both "with and against the gender stereotypes of the nerd and the mad scientist" while integrating many core characters of the sitcom genre, wrote Margaret Weitekamp,a curator at Smithsonian National Air and Space Museum in Washington, in a 2015 essay about the series.

Weitekamp wrote that the show was distinctive with "a sympathetic and nuanced depiction of scientists", which included a more diverse group of scientists by gender, ethnicity, and scientific subfields than usually seen in either television or movies.

One of the main characters, Amy, for example, was a female neurobiologist who became a Nobel laureate together with her husband Sheldon. In her acceptance speech in the show, she said "go for it" to "all the young girls who dream about science as a profession".

"It is the greatest job in the world. And if anybody tells you you can't, don't listen," she said.

"Let's just remind everyone that@missmayim [Mayim Bialik] has a real PhD in neuroscience ... When she gave this speech... she meant it," wrote Janet Johnson, a clinical assistant professor at the University of Texas in Dallas on Twitter.