I need help with level 4 after I kill the ice things and I get back to the top what do i have to do??????????????? i'm really confused

As you probably know, there are four ( i think) towers. You just go around to them all and find the one you can climb to the top in. There should be a broken bridge somewhere. If you kneed further help go to this website. Its a Indiana Jones Walkthrough. www.canofworms.com. The look on the left for current walthroughs or something. The scrool down to find (and I quote) "infernal machine". That really helped me.