Living conditions have improved greatly since 2000, even for the world’s poorest people, but billions remain mired in “layers of inequality.” That is the assessment from the Bill & Melinda Gates Foundation’s third annual report on progress toward U.N. Sustainable Development Goals.

ON THIS DAY IN AMERICAN HISTORY On September 17, 1976, NASA unveils the first Space Shuttle prototype, the Enterprise. Designed for atmospheric test flights only, Enterprise did not have engines or a heat shield. Its first test was conducted on February 18, 1977, when it was carried aloft on a Boeing 747. Later that year, it flew on its own for the first time. These so-called “Approach and Landing Tests” paved the way for real missions when the shuttle re-entered the atmosphere and glided toward a landing similar to an airplane. Enterprise was named after the fictional spaceship in the popular science fiction franchise, Star Trek . Most of the original cast attended Enterprise’s unveiling.

U.S. President Donald Trump says any American military attack on Iran would be proportionate to the attacks carried out on oil facilities in Saudi Arabia.

Supporters of Islamic State are rejoicing at what appears to be a new message from the terror group’s reclusive leader, in which he promises the war against the United States and its allies is far from over.

VIDEO: A watery grave of old sunken ships has been designated the newest national marine sanctuary in the United States. Located in Maryland about 60 kilometers south of Washington, the “ghost fleet” rises like an apparition out of the water when the tide is low.

Afghanistan’s President Ashraf Ghani escaped an attack on his campaign rally in Parwan province that killed 24 people and wounded more than 30 others Tuesday.