Nevado del Ruiz is a 5389 metre high volcano in colombia south america.
The town of armero is 74 kilometres away.
The volcano had erupted before in 1845.
That erution killed handreds of people in Armero.
But by 1985,most people had forgotten about the dangers
of the volcano and the town's population had grown to almost 30000.
Scientists had known for over a year that the volcano was active
but when they tried to warn people of the danger
nobody believed them.