With the mass shooting in Aurora, Colo., that left 12 people dead and 38 others injured, authorities can now add another horrible incident to the long list of random massacres that have plagued the United States.

While officials claim to be working around the clock in an effort to raise awareness and protect innocent civilians from happenings like this most recent one, it seems as if these random shootings are taking place with terrible frequency.

After the Columbine high school massacre of 1999, filmmaker Michael Moore even made a documentary, "Bowling For Columbine," that explored the possible causes for that shooting and other random acts of gun violence.

In one memorable scene from the movie, Moore discovers how a bank in Michigan would give customers a free hunting rifle when they made a deposit of a certain size into a time deposit account. During the scene, a camera follows Moore as he goes to the bank, makes his deposit, fills out the forms and awaits the result of a background check before walking out of the bank carrying a brand new Weatherby hunting rifle.

Just before leaving the bank, Moore asks the teller, "Do you think it's a little dangerous to be handing out guns at a bank?"

Precautions in high schools and universities have been taken since the Columbine school shootings and others like it. But if history is any guide, chances are the Colorado movie theater massacre most likely will not be the last mass shooting in the United States.

Here are five of America's most deadly shootings. 

James Holmes is set to make his first court appearance at around 11:30 a.m. EDT, giving the American public its first look at the suspect since his arrest in an attack that left at least 12 moviegoers dead and 58 others injured.

On May 18, 1927, three bombs went off at the Bath Consolidated School in Bath Township, Mich., killing a total of 58 people, including 38 elementary school children, two teachers, four other adults and the bomber himself. The bomber was school board treasurer Andrew Kehoe, 55, who was ostensibly enraged about a property tax levied to fund the construction of the school building.

On April 17, 2007, Seung-Hui Cho shot and killed 32 people and wounded 17 others at Virginia Polytechnic institute and State University in Blacksburg, Va. In two separate attacks, approximately two hours apart, the Virginia Tech killer unleashed fury on his peers before turning the gun on himself. The massacre is the deadliest shooting incident by a single gunman in U.S. history.

On on August 1, 1966, Charles Joseph Whitman killed 16 people and wounded 32 during a shooting rampage at the University of Texas at Austin. Whitman, a former marine, killed three of his victims inside the university's tower and 10 others from the 28th floor observation deck of the University's 307-foot administrative building -- one, Karen Griffith, died a week after the shooting from her wounds. Whitman was shot and killed by Austin police officer Houston McCoy.

Dylan Klebold (right) is holding a Tec-9, while Eric Harris is seen with a 995 carbine and his sawn-off shotgun when they killed 13 people and injured several more at Columbine High School. Both students concluded the massacre by committing suicide.

On July 18, 1984, James O. Huberty opened fire inside a McDonald's restaurant in the San Ysidro section of San Diego, Calif. The shootings resulted in 21 people killed and 19 others injured. In response to the incident, the city of San Diego increased training for special units and purchased more powerful firearms to counteract future situations. The incident also led police departments across the U.S. to provide their officers with higher power firearms and training for stopping violent criminals and keeping all those around them safe.