Revolutionary War
Revolutionary War

Floodlights illuminate the Albert P. Murrah Federal Building in Oklahoma City, as rescuers searched for bodies the day after the April 19, 1995 bombing. The blast killed 168 people and injured 500. See revolutionary war pictures.

BOB DAEMMRICH/AFP/Getty Images

"April is the cruellest month."

At least that's what T.S. Eliot said when he penned "The Waste Land" all the way back in 1922. Maybe the guy wasn't a fan of rain. Or spring. Perhaps the old fella just didn't like paying taxes. Or maybe Eliot had his finger on the pulse of something more sinister that tends to rear its head this time of year.

It's the month when spring blooms, baseball season hits full swing and procrastinators across the U.S. wait until the very last minute to pay Uncle Sam his cash, but April has another, more dubious distinction as perhaps the most violent month of them all.

It wasn't long after the Boston marathon bombings that conspiracy theorists noted that the brutal explosions that killed three people and injured another 264 went off just a few days before the 18th anniversary of the Oklahoma City blasts that killed 168 and injured 500. In the latter attack, bomber Timothy McVeigh said he targeted the Albert P. Murrah federal building for the 1995 bombing as payback for the law enforcement raid on David Koresh's Branch Davidian compound in Waco, Texas, on the same day two years earlier [sources: Reuters, Grinberg].

That's not to mention a slew of other acts of widespread violence that have made April a bloody month, including shootings at Columbine High School in Colorado in 1999 and Virginia Tech University in 2007. Those two events alone left 45 dead and another 38 injured. Meanwhile, U.S. civil rights leader Martin Luther King Jr. was gunned down in a Memphis hotel room on a hot April night in 1968, setting off riots across the country that would go on for days [sources: Reuters, Grinberg].

So what exactly is it about April that makes the world's terrorist element spring into action?