Stay away from the brown recluse spider, one of the most dangerous arachnids on Earth. It can be found outdoors near rocks or in the woods -- or, chillingly, indoors in dark places, including corners and furniture. Its bite can cause lesions that lead to gangrene.
Click through the gallery to learn about more of the world's most dangerous spiders.Shutterstock
The black widow spider is found all over the globe. Its bite can produce vomiting and achiness, although it's not usually fatal. The black widow is usually identified by a black body with red hourglass marking. Shutterstock
A brown widow spider, which also has an hourglass-shaped marking on its abdomen, is slightly less venomous than the black widow. It's thought to live in most of the world's most tropical locations as well as in the southern United States. These nocturnal creatures have painful bites that can result in serious swelling and redness.Shutterstock
Although they resemble the harmless tarantula, Brazilian wandering spiders, known for building webs in bananas, are considerably more dangerous. The South American specimen may well be the most venomous spider on the planet. Its bite could be life-threatening.Shutterstock
The Sydney funnel-web spider, generally found in Australia, also gives a painful bite. The funnel-web spider's venom, which attacks the central nervous system, has caused the deaths of more than a dozen people over the past 100 years.Shutterstock
This wolf spider, seen here with baby spiders on her back, is a type of spider that usually lives on the ground. It will bite humans, but its venom usually just causes swelling.Shutterstock