Rembrandt, Picasso, Leonardo da Vinci, Vincent van Gogh. Which of the world's most revered artists do you most appreciate? And what would you give to see their greatest masterpieces on display? Whatever your taste in art, we owe our gratitude to those who have worked passionately to house and protect such valuable treasures so they may also be shared with the world.

Throughout history, however, and specifically because of their great worth, there are those who have vied to steal valuable pieces of art for personal gain. In fact, according to the FBI Art Theft Program, art theft amounts to an estimated $4 to $6 billion each and every year. Here is a look at three of the largest art crimes in history.

The Looting of the Baghdad Museum, 2003

Call it the spoils of war. When the United States rolled into Baghdad in April of 2003 just after the start of the Iraq War, the National Museum of Iraq was left unprotected. A museum of cultural and historical significance, the site was pillaged and looted of some 15,000 precious artifacts over the course of three days. The stolen items included a large collection of ancient Sumerian seals thousands of years old. In the ensuing years, thousands of items were returned or recovered, but the seals remain missing to this day.

Mona Lisa, stolen from the Louvre, 1911

In many ways, it makes no sense to steal a priceless work of art. Art heists are well advertised to the public, so it would be a fool's errand to try to sell the stolen piece. And if you're on the receiving end, how do you explain where and how you obtained it?

Despite the obvious conundrum, in August of 1911 an Italian worker by the name of Vincenzo Preuggia, hired to clean and reframe paintings at the Louvre, did just that. He removed the famous lady from her frame and, concealing the piece with his work smock, carried her out the door. He kept it hidden in his apartment in a trunk for two years.

Eventually, ostensibly in hopes of receiving either a payment or reward for returning the masterpiece to his home country, Peruggia contacted a Florence art dealer offering up the painting for 500,000 lire. Peruggia spent seven months in prison for his foolish plan, and the Mona Lisa was returned to the Louvre.

Boston's Isabella Stewart Gardner Museum, 13 masterpieces stolen in 1990

In the early hours of March 18, 1990, two men purporting to be police officers were granted entrance to the Museum by two security guards who were told they were checking on a disturbance. The guards were quickly overtaken and tied up, the thieves making away with 13 priceless works of art by such masters as Rembrandt, Degas, and Vermeer.

The theft generated many leads, most of which came to a dead end, but one person of interest, Robert Gentile, who reportedly had ties to the mob, remained in law enforcement's sights. They suspected Gentile because the widow of another mobster claimed her husband gave two of the stolen paintings to him. In addition, a subsequent search of his home garnered a list of all the stolen pieces and individual estimations of their worth. Throughout the years, however, Gentile repeatedly denied any involvement. He died in 2021 leaving the police no closer to solving the mystery.

Just as it was with Gentile, an accused person's culpability in an art heist isn't always black and white. That's why it's important for anyone accused in such a matter to seek out an experienced criminal defense attorney. Law firms are well-versed in state and federal criminal law and specialize in defending their clients against serious criminal charges.