In History, Today on July 7

A sniper attack occurred in Dallas, Texas, during a protest against police shootings of African Americans. Five police officers were killed, and nine others were injured. The gunman was later killed by a robot-delivered bomb.

A train carrying crude oil derailed in Lac-Mégantic, Quebec, Canada, causing a massive explosion and fire that killed 47 people and destroyed much of the town's center.

The final mission of NASA's Space Shuttle program, STS-135, was launched. The shuttle Atlantis carried a crew of four to the International Space Station, marking the end of the 30-year Space Shuttle program that began with the launch of Columbia in 1981.

The Live Earth concerts, a series of music events, were held across seven continents to raise awareness about climate change. Organized by former U.S. Vice President Al Gore and the Alliance for Climate Protection, the concerts featured over 150 musical acts and reached an estimated global audience of 2 billion people.

A series of coordinated suicide bombings targeted the London public transport system during the morning rush hour, killing 52 civilians and injuring over 700. The attacks were carried out by four Islamist extremists and marked the deadliest terrorist incident in the United Kingdom since the 1988 Lockerbie bombing.

The first draft of the complete human genome is announced by scientists at the Human Genome Project.

The United States' Secretary of Agriculture Dan Glickman declared a ban on the slaughter of downer cattle, following an outbreak of mad cow disease concerns.

Boris Becker became the youngest champion in Wimbledon history at age 17 by winning the men's singles title.

US President Ronald Reagan nominates Sandra Day O'Connor to become the first female member of the Supreme Court of the United States.

President Dwight D. Eisenhower signed the Alaska Statehood Act into law, which paved the way for Alaska to become the 49th state of the United States.

Elvis Presley makes his radio debut when WHBQ Memphis played his first recording for Sun Records, "That's All Right."

Reports of a UFO crash in Roswell, New Mexico, spark widespread interest and conspiracy theories.

Mother Frances Xavier Cabrini becomes the first American to be canonized as a saint by the Roman Catholic Church.

U.S. occupation forces landed in Iceland to ensure the nation's security during World War II.

The Marco Polo Bridge Incident occurs, marking the beginning of the Second Sino-Japanese War.

Construction of the Hoover Dam begins on the Colorado River.

Sliced bread is sold for the first time by the Chillicothe Baking Company of Chillicothe, Missouri.

U.S. President William McKinley signed the Newlands Resolution, annexing Hawaii as a United States territory.

The United States annexes California during the Mexican-American War when Commodore John D. Sloat declares California a part of the United States.

The Treaty of Tilsit is signed between Napoleonic France and Russia, establishing the two powers as allies and reorganizing numerous European territories.

The British Museum was established by an Act of Parliament.

The Raid of Rathlin Island occurs during the Irish Confederate Wars, where English troops under Sir John Norris attacked and massacred Scottish clansmen of the MacDonnell family.

Jacques Cartier makes contact with indigenous peoples of the Gaspé Peninsula in present-day Quebec and claims the territory for France.

The Spanish conquistadors, led by Hernán Cortés, defeat a numerically superior Aztec army at the Battle of Otumba.

A retrial verdict acquits Joan of Arc of heresy, 25 years after her execution.

King Edward I of England dies, and is succeeded by his son, Edward II.

The Battle of Capo Colonna occurs, where the forces of the Holy Roman Empire under Otto II are defeated by the Muslim forces of the Emirate of Sicily.

The Siege of Constantinople by the Avars and Persians begins, marking a significant event in the Byzantine-Sassanian War.