THERE ARE A FEW THINGS I won’t add to my bucket list — stepping into an active volcano is one of them. I’ll just live vicariously though Sam Cossman, George Kourounis, Geoff Mackely and Brad Ambrose, who are some of the first people to closely explore the Marum Crater in Vanuatu. According to Cossman, “More people have visited the moon than the fiery bottom of this spectacular and deadly place.”