The Brazilian wandering spider is the deadliest spider in the world. The Sydney funnel-web spider can kill a person within an hour if you don't act in time.
The Southern Black Widow is also a very dangerous poisonous spider found mainly in the USA, Canada and Latin America. The nurse's thorn finger can poison a person with its bite, but the poison is weak enough that it doesn't kill you. The redback spider is native to New Zealand and Australia and can be easily recognized by the red stripe on its back.