Five years ago, he started live-tweeting World War Two

The Washington Post has an article by Brian Fung about a guy and World War Two:

Lord Lovat leads British Commandos to capture village, is offered champagne by the French café owner: "Not now, I'm working."

British commandos land on Sword beach, with Scottish bagpiper Bill Millin playing Highland Laddie over gunfire.

In 2011, a 24-year-old history buff named Alwyn Collinson had a simple idea: tweet the Second World War as if it were actually happening, live, today. The goal, as he described it then to The Telegraph, was to "help people feel like they're there", sprinkling his coverage of the war with period photographs and little anecdotes to flesh out the major plot points, which began with Hitler's invasion of Poland in 1939.
Now, after years of tweets about Rommel in Africa and the Battle of Britain, Collinson has finally reached a pivotal moment in the war's history: he's live-tweeting D-Day on its anniversary, down to the exact hour that the invasion began. It's an amazing achievement because it means followers of @RealTimeWWII are now re-living D-Day after a long period of enormous buildup.
But one of the things that makes @RealTimeWWII so compelling is the way it elevates lesser-known facts and photographs, lending the sense that you're watching more than just a documentary or reading a textbook that simply goes through the motions.
Live-tweeting D-Day is not a new idea. But what makes @RealTimeWWII unlike the others is that Collinson has been chronicling the entire war with his feed, and it has finally built up to this historic day.
The Allies battled the Axis for another year after the initial invasion of Europe. So, too, will Collinson soldier on, but today marks an epic moment for a commensurately epic project.

Rico says that's some serious OCD...