In 1876, Colorado was admitted as the 38th state.

In 1907, the U.S. Army Signal Corps established an aeronautical division, the forerunner of the U.S. Air Force.

In 1936, the Olympics opened in Berlin with a ceremony presided over by Adolf Hitler.

In 1944, an uprising broke out in Warsaw, Poland, against Nazi occupation; the revolt lasted two months before collapsing.

In 1957, the United States and Canada announced they had agreed to create the North American Air Defense Command (NORAD).

In 1966, Charles Joseph Whitman, 25, went on an armed rampage at the University of Texas in Austin that killed 14 people, most of whom were shot by Whitman while he was perched in the clock tower of the main campus building. (Whitman, who had also slain his wife and mother hours earlier, was finally gunned down by police.)

In 1971, the Concert for Bangladesh, organized by George Harrison and Ravi Shankar, took place at New York’s Madison Square Garden.

In 1975, a 35-nation summit in Finland concluded with the signing of a declaration known as the Helsinki Accords dealing with European security, human rights and East-West contacts.

In 1977, former U-2 pilot Francis Gary Powers, working as a traffic reporter for KNBC-TV in Los Angeles, was killed with his cameraman, George Spears, when their helicopter ran out of fuel and crashed; Powers was 47.

In 1981, the rock music video channel MTV made its debut.

In 2007, the eight-lane Interstate 35W bridge, a major Minneapolis artery, collapsed into the Mississippi River during evening rush hour, killing 13 people.

In 2013, defying the United States, Russia granted Edward Snowden temporary asylum, allowing the National Security Agency leaker to slip out of the Moscow airport where he had been holed up for weeks.

In 2014, a medical examiner ruled that a New York City police officer’s chokehold caused the death of Eric Garner, whose videotaped arrest and final pleas of “I can’t breathe!” had sparked outrage.

Ten years ago: The U.S. House of Representatives passed, 269-161, emergency legislation to avert the nation’s first-ever financial default; Arizona Congresswoman Gabrielle Giffords returned to the House for the first time since being shot in Jan. 2011 to cast a “yes” vote.

Five years ago: The United States launched multiple airstrikes against Islamic State militants in Libya, opening a new front against the group at the request of the United Nations-backed Libyan government.

Vice President Joe Biden officiated a gay wedding, a first for the early proponent of same-sex marriage as he presided over the union of Joe Mahshie and Brian Mosteller, both longtime White House aides, at the U.S. Naval Observatory in Washington.