As undesirable as it might be, we're pretty much surrounded by spiders at all times, and if the arachnids' generally unsettling appearance wasn't enough to make that a vertiginous thought, consider ...

A subgroup of air-breathing, terrestrial (land) arthropods, spiders are not actually insects but rather belong to the Class Arachnida (a.k.a. arachnid). Besides spiders, other arachnids include ...