jeff mackley is an adventure list and this is a lava lake at the bottom of ambren island. it's a chain of volcanic islands in the south pacific. >> he is standing at the edge of a volcanic area that is 2100 degrees fahrenheit. he's wearing a heat resistant suit. he's also wearing breathing apparatus to be there. took them an entire expedition, about 35 days to achieve this. they had to run a string of ropes down into the crater of this volcano, withstand crummy weather. no man has stood where he has. if you slip and fall, you're toast. >> he looks like he's standing on the surface of the sun. >> so explain what it feels like to stare is jeff mackley. >> it's only truly hot when you're on the edge. we did a test and looked over the edge without the breathing apparatus and the suit. you could stand the heat for roughly six seconds and then you had to run away. >> jeff, how close did you get to the lava. >> probably 80 feet. >> what is your body feeling? what are you seeing? what's the experience like? >> people have said it looks like you're standing on the surface of the su