Eighteen years ago, more than 60% of Americans watched as the worst terror attack ever to occur on U.S. soil unfolded on television. That up-close view of the murders of almost 3,000 people jolted Americans out of the sense of security they’d enjoyed at least since World War II.

ON THIS DAY IN AMERICAN HISTORY On September 11, 2001 al-Qaida terrorists crash two planes into the twin towers of the World Trade Center in New York. Another team of terrorists flew a plane into the Pentagon near Washington, DC, and another plane crashed in a field in Pennsylvania after being taken over by passengers who had found about about the ongoing attacks. Nearly 3,000 people were killed. In response to the attacks, the U.S. invaded Afghanistan and later, Iraq where over 4,000 U.S. service members died. The war in Afghanistan continues.

Since the terror attacks of Sept. 11, 2001, there is one question that has rarely strayed for long from the minds of a majority of people living in the United States: Are we safe?

Eighteen years after the deadliest terror attack on U.S. soil, the world’s military spending is at an all-time high. According to data from the Stockholm International Peace Research Institute, military spending was $1.8 trillion in 2018 alone, which the institute called a “worrying trend.”

VIDEO: Artists are bringing their artwork into a new dimension using augmented reality. The technology allows for artwork to appear to come to life. For example, at a recent demonstration a mural of a dinosaur appeared to show the dinosaur move and run away when seen using a smartphone.

VIDEO: Russian voters this week dealt the party of President Vladimir Putin a heavy blow in local elections that were marred by street protests and police crackdowns in Moscow. Putin’s United Russia party lost control of key regions, including the capital, raising questions of how long he may continue to lead what some analysts say is an increasingly restive nation.