Enlarge ImageThe future is here! October 21, 2015, is “Back to the Future Day.” Universal Pictures

Never before have we been so nostalgic for something that never happened.

For the better part of three decades, fans of the “Back to the Future” movie trilogy have eagerly waited for October 21, 2015 — today! — to celebrate a movie that wistfully imagined what California would look like in the future, err, present. Enthusiastic devotees have clogged the Internet with images inspired by the movie. There are hoverboards, self-lacing sneakers and flying cars, all products we wish would go on sale.

Not familiar with B2TF, as the series is abbreviated? It follows Michael J. Fox’s Marty McFly and his friend Doc Brown as they time-travel in a rehabbed DeLorean, the sleek, high-end car that in the ’80s had a fascinating story of its own. Oh yeah, there are also plenty of photos of DeLoreans floating around the Internet now. Enlarge ImageMichael J. Fox starred as Marty McFly in the popular Back to the Future trilogy. Universal Pictures

“The Back to the Future trilogy is simply iconic,” said Martin Archer, a physicist and popular radio personality in the UK, who will introduce a showing of “Back to the Future Part II” at a London cinema. “It continues to capture the imagination.”

The Internet, which B2TF didn’t prognosticate, is unsurprisingly the epicenter of fan activity.

Facebook said that roughly a million people have joined more than 4,500 B2TF-themed events on the social network. Similarly, more than half a million B2TF-related tweets have been posted to Twitter in the past month alone, according to Union Metrics, a San Francisco-based social media analytics company.

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Many of those conversations on social media discuss what the B2TF series got right about the future. Wearable tech, drones and videoconferencing are among the technological feats the series is given credit for accurately predicting. There’s also an explosion of chatter on the Internet about B2TF’s prediction that the Chicago Cubs will finally get a World Series victory. They’re only eight wins away.

Enlarge Image“Back to the Future Day” mentions on Twitter spiked in the week ahead of October 21, 2015, says Union Metrics. Union Metrics

Suzette Valle, the author of children’s cinema guide titled “101 Movies To See Before You Grow Up,” says part of B2TF’s allure is that it gave moviegoers an innocent-yet-exciting glimpse of what the future might look like.

“The concept of time travel that didn’t involve spacemen or living on an isolated planet, but instead simply staying in an updated version of our same neighborhoods, was a different concept for moviegoers in…