One more event before the South American trip is a climb up the CN Tower in downtown Toronto on the 19 April (www.wwf.ca/cntower). 144 flights of windowless stairs ! A different challenge and for a very good cause.One more event before the South American trip is a climb up the CN Tower in downtown Toronto on the 19 April (www.wwf.ca/cntower). 144 flights of windowless stairs ! A different challenge and for a very good cause.