PHOENIX - It's a question that's baffled thousands for more than two decades. A mysterious sight that no one has ever really been able to explain. Tuesday, March 13, 2018, marks the 21st anniversary of the "Phoenix Lights" first seen back in 1997.

Every year witnesses and researchers get together around the anniversary to bring the event back to life. Organizers say to date, the "Phoenix Lights" have never been recreated or explained.

Back in the late 90s, a string of bright lights in the shape of a "V" lit up the Phoenix sky. Some say they saw physical crafts behind the lights, and others say the lights were crafts. Other theories point to flares or a military drill.

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But still today, all of these years later, there are no official answers. This weekend, Dr. Brad Evans is coming forward for the first time in 21 years to talk about his personal experience with the lights. He says he was driving with his family on I-10 from Tucson to Phoenix and witnessed the phenomenon.

Dr. Lynne Kitei organizes the "Phoenix Lights" event every year in Scottsdale and says she saw something that night she never expected to see.

"Most anomalies can be explained," Kitei said. "I must stress that only a small percentage cannot. Just because we don't have the technology yet to definitively define what these things are doesn't mean they're not real. We may just be looking on the AM dial for an FM frequency."

The anniversary event is Sunday, March 18, at the Scottsdale Shea Harkins at 1 p.m.