Before we begin, let’s get this out of the way: AyeeeeEEEEEEeeeeeee!!! Back in 2009, the Baltimore Wastewater Treatment Plant put in a call of the most unusual nature when they reported a giant spider web that covered almost 4 acres of their huge indoor water treatment facility. Scientists estimated the giant spider web contained well over 107 million spiders! See the 4-acre spider web in the picture above. The culprits were orb-weaver spiders that in some cases, filled over 95% of the various sections of the plant. The spider webbing was so heavy, it pulled light fixtures from the ceiling. There are over 10,000 species of orb weaver spiders. In all, they make up about 25% of the planet’s spider population.