What was significant about President Eisenhower's use of the National Guard to protect the Little Rock Nine?

When Governor Faubus ordered the Arkansas National Guard to surround Central High School to keep the nine students from entering the school, President Eisenhower ordered the 101st Airborne Division into Little Rock to insure the safety of the "Little Rock Nine" and that the rulings of the Supreme Court were upheld.

Explanation:

the tallest building in the western hemisphere and the sixth tallest building in the world

ww1 weapons: tank. tanks were used for the first time in the first world war at the battle of the somme. they were developed to cope with the conditions on the western front. the first tank was called 'little willie' and needed a crew of 3.