Climbing is Nathan's official sport

Nathan has taken to climbing. I guess it has always has had an affinity for it. When he was just a year old he started perching, and I do mean perching, on this butter cookie tin that was in our living room. He would put his feet one by one on the edge, not the middle, and try to stand up. When you are only 1.5 ft tall being 5" off the floor is a big deal. So the other day he climbed up on the small filing box that is in the corner of the living room. He was so excited bobbing up and down on the box reaching for the things that he could now get to. He would climb up and down and I would move things out of reach and it was all going well 'till he took a tumble and busted the inside of his upper lip, don't ask me how. Mouth injuries bleed a lot you know; so 5 min. later he is feeling fine and ready to go but he is still bleeding and I am trying to make sure that he has all his teeth in between bites of Popsicle which I am hoping will help stop the bleeding. I had been mopping up the blood with a damp washcloth and now he wanted to wipe everyone face with it which was just icky. Did this deter his climbing ambitions...of course not. I was in the kitchen just days later on the phone with my mom. Nathan was running around the living room and I could just barely see the top of Nathans little head going this way and that over the bar that separates the kitchen from the living room. Now I can not see more than the top of his head because the bar is about chest high. Suddenly Nathans little face comes up over the bar grinning at me and as he is as proud as he could be. I was in shock. You know when you see something that your brain doesn't believe is possible and your mouth feels that it needs to state it just to see if it sounds better out of your head. Out it comes to my mom who, if you remember, I am on the phone with, "Nathan's head just came up over the bar." Just like that; my mom, quickly assessing the situation, says that she will let me go and gathering my wits about me I run into the living room just as Nathan begins to explore the new range of his reach. He had used the a fore mentioned butter cookie tin to get on the chair under the bar and from there he climbed on the back of the chair and tada! we are looking over the bar. So how do I put a stop to this dangerous escapade? I have no idea. So far it has not happened again and so I am just keeping my fingers crossed. So the real question is... what is next? Everest?