Nevado del Ruiz
The lahars destroyed many houses and towns. The town of Armero was completely covered by debris, killing approximately 21,000 people (three-fourths of the population), as well as affecting 13 other villages.  The eruption caused an estimated 23,000 deaths, 5,000 injuries, and destroyed more than 5,000 homes. This was the second deadliest volcanic disaster in the 20th century, ousted only by the 1902 eruption of Mount Pelee, and the fourth deadliest eruption in recorded history.  In addition, it was the deadliest lahar in recorded history, and Colombia's worst natural disaster.