The British Parliament passed a law granting independence in July 1947. The law gave people only one month to decide which country they wanted to live in and to move there. As millions of people began to move, more violence broke out.
Calderas form when an enormous magma chamber under, what was probably a pretty ginormous volcano, empties and collapses, causing the land above it to collapse as well. An explosive caldera-forming eruption has never been witnessed first hand, but we know that they should pretty fearsome spectacles. Much smaller calderas atop effusive volcanoes (hawaiian style) have been observed. So, formation: maars form when a vent intersects groundwater and blasts out the overlying material.
The 79 A.D. eruption of Vesuvius was the first volcanic eruption ever to be described in detail. From 18 miles (30 km) west of the volcano, Pliny the Younger, witnessed the eruption and later recorded his observations in two letters.