43 years ago - Barry Allen is born.
25 years ago - 18-year-old Barry begins studying chemistry & forensic science.
19 years ago - 24-year-old Barry first meets Iris West.
18 years ago - 25-year-old Barry gains his speed force powers in a lab accident & becomes the Flash.
16 years ago - 27-year-old Barry is a founding member of the Justice League, and he first meets Wally West, Iris's nephew.
15 years ago - 28-year-old Barry is first confronted by Eobard Thawne, a refugee from a lost future timeline and expert at speed force manipulation who is obsessed with using Barry to return home.
14 years ago - 29-year-old Barry takes on Wally West as Kid Flash when he gains similar powers in a lab accident.
11 years ago - 32-year-old Barry marries Iris West.
10 years ago - 33-year-old Barry goes to Themyscera with Diana Prince, Etta Candy & Hal Jordan, becoming one of the only men to ever set foot on the island.
9 years ago - 34-year-old Barry is expelled from the Justice League when Eobard Thawne attempts to draw him into the Speed Force by trying to Murder Iris West. When he tries again they are both drawn inside. Barry outruns him, managing to save Iris by depositing her in the 30th century. before is absorbed into the Speed Force, while Eobard is killed.
The legacy of Barry Allen is further reaching than almost any other character in DC. He's the very first character of the SIlver Age, and the very first classic character to pass on his legacy to his protege.
He's also the character who's return marked the true downfall of DC's continuity. There were mistakes before him, but his death was too big, and too much a part of the bedrock of the story. Once he returned, there was nothing left for DC to do but push reset on everything. It could be argued that Barry is responsible both for the beginning and the end of the DC universe as we know it.
Obviously, we've left his story alone. We've kept his classic origin and story, removed any of the time travel that permeated his early adventures, and allowed him to remain what he's always been, what he's better at than anyone: the greatest Legacy DC has.