They trip off the tongue: Vesuvius. Krakatoa. Mount Saint Helens. Santorini. These are just some of the big volcanic eruptions known to have affected humans and other animal and plant life around the world.
Think of an eruption even bigger -- bigger than those four eruptions combined -- and you will get Tambora, the Indonesian volcano that killed more than 92,000 people in 1815, and whose influence was felt for many years. In fact, so great was that explosion, so massive was the amount of crap hurled into the air, that summer did not come to most of the planet in 1816, killing crops, animals, and causing the starvation deaths of untold number of people.
Now, just imagine what would happen if such an eruption occurred today.
You can listen to a story about Tambora here.