Ever since the terrorist attacks on September 11, 2001, thousands of 9/11 first responders have fallen victim to cancer and other terminal illnesses.BETH A. KEISER/AFP/Getty Images9/11 first responders search through the rubble of the World Trade Center on September 13, 2001. On September 11, 2001, American life changed forever. Nineteen al-Qaeda terrorists hijacked four U.S. passenger planes and launched attacks on New York City and Washington, D.C. As the disaster unfolded, thousands of 9/11 first responders rushed to help the survivors.

Between 1830 and 1850, the U.S. government forced the Cherokee, the Choctaw, and other tribes off their ancestral lands with deadly force in what's become known as the Trail of Tears.Throughout the 1830s, President Andrew Jackson ordered the forced removal of tens of thousands of Native Americans from their homelands east of the Mississippi River. This perilous journey to designated lands in the west, known as the Trail of Tears, was fraught with harsh winters, disease, and cruelty.

What happens when glaciers and volcanoes convene? These stunning volcanic rivers.Source: Andre Ermolaev When it comes to size, Iceland is roughly the size of Ohio, but within that relatively humble space are hundreds of volcanoes; so many that in the last 500 years, Iceland alone has been responsible for 30 percent of the world’s lava flow. Pair this with glaciers that also populate the landscape, and you have the perfect storm of natural occurrences that make stunning aerial photographs like these possible.

Sometimes called the "Las Vegas of the ancient world," the sunken settlement of Baiae was one of its era's most hedonistic resort towns for wealthy Roman elites.About 150 miles south of Rome, a resort for ancient Roman elites once stood between Mount Vesuvius and the vast Mediterranean Sea. This luxurious place was known as Baiae (sometimes also spelled as Baia). Centuries ago, the site was the ancient equivalent of the modern-day Las Vegas, a place where secrets, intrigue, and scandal were born.

When police raided serial killer John Wayne Gacy's house at 8213 West Summerdale Ave. in Chicago's Norwood Park in 1978, they uncovered 29 bodies.Realtor.comThough it looked like a normal suburban ranch, John Wayne Gacy’s house in Norwood Park, Illinois was actually the site of 33 brutal murders in the 1970s. In the 1970s, a nondescript house sat at 8213 W. Summerdale Avenue in Chicago, Illinois. It didn’t look like much from the street.