What is the world's most venomous spider?

The world's most venomous spider is the Sydney funnel-web spider (Atrax robustus), which is found in and around Sydney, Australia. These spiders are highly venomous and are responsible for most spider bites in Australia. The venom of the male funnel-web spider is six times more toxic than that of the female, and it can be deadly to humans.

The venom of the Sydney funnel-web spider contains a neurotoxin that can cause symptoms such as sweating, muscle spasms, vomiting, and increased heart rate. Without treatment, a bite from this spider can be fatal within hours. However, there is an antivenom available that can save lives if administered quickly.

It's important to note that while the Sydney funnel-web spider is considered the most venomous in the world, there are other spiders with venom that is also highly toxic to humans. Some examples include the Brazilian wandering spider, the brown recluse spider, and the black widow spider.