Halloween's over, which can mean only one terrible thing: these photos are not from a haunted house. They are real. These photos are from a paper published by the Entomological Society of America in 2010, documenting scientists' visit to the Black River Wastewater Treatment Plant in Baltimore after their managers put out a desperate plea for help from experts in 2009 to deal with an "extreme spider situation."

I see your problem here: this building is not currently on fire.

What you are looking at is an example of spiders from multiple species of the orb-weaver family cooperating to build a mega-nest that covered the whole 4-acre facility—populated by an estimated (not just estimated, but conservatively estimated) 107,000,000 spiders, reaching densities of 35,176 spiders in each square meter in the most crowded spots.

"Just peel back the web like a piece of sheet metal. That's how webs work, right?"

Stick your arm out and wave it around in a circle. Congratulations, you just touched 35,176 spiders. Are you feeling itchy? I'm feeling itchy.

I am so glad I gave up on science long before getting a degree to do this. 
(via Entomological Society of America)

Sources: Entomological Society of America | Wired | Geekologie | Sploid