Spider's Nest

From PathfinderWiki

The Spider's Nest is a 200-year-old crater several miles in diameter. It was formed when a gigantic explosion shook the eastern Hoarwood Forest, and out poured plumes of smoke, fire, and giant spiders. Queen Yelizaveta sent her armies to defeat this sudden spider horde before it could spread much beyond the forest, and they succeeded. Since then, few have explored the area, and none knows the cause of the original explosion.1