There is a really interesting story in today’s Asia Times Online. 
Short version:
- Melocanna baccifera is a bamboo prevalent in some states in India
- It mass-blooms every 48 years
- The seeds feed rats
- The rat population explodes
- The rat over-population goes after agricultural products
- Then follows human famine, civil unrest, revolution
Nature creating political cycles on schedule – fascinating.
Are there more cases like this one?
See also:
The Day After: Flowers of Doom