A 10 kilometre floodplain infested with 25,000 tarantulas.
http://www.smh.com.au/environment/animals/field-of-screams-the-mystery-of-maningridas-25000-tarantulas-20150623-ghv2ip.html
They are also a 'diving ' tarantular - the hairs hold a bubble around their body and they can live underwater
.... so when you go swimming ....