Opacity is on of the biggest urban exploration websites.
www.opacity.us
US based Urban Explorers.
www.urbanexplorers.net
Talk Urbex covers everything from very knowledgeable exploration's and a handy forum
www.talkurbex.com
Danvers State Hospital.
www.danversstateinsaneasylum.com
28 Days later is a UK based UE forum.
www.28dayslater.co.uk
Infiltration is one of the first UE websites.
www.infiltration.org
Urban-exploration is a French based site.
www.urban-exploration.com
Dark passage is a American based site & has been
around since 98.
www.darkpassage.com
Spanish website/blog  & friends of the site.
www.recurriendoalpasado.blogspot.com

Other great sites,
Abandonded Places
Weburbanist
Urban exploration resource website



Have a site to recommend or wanna exchange links?

Bradd Earea NZ explorer
www.braddearea.com

Bradd is the new kid online,  he's slowly putting his stuff on his very own website. With write up's and HDR photography, so why don't you check him out!

Strange Occurrences
Wellington based paranormal group
www.photospace.co.nz/strange_home.htm