Almost all carbon fiber, with a 130' tall rigid wing sail. It's controlled hydraulically, but the America's Cup rules this time around said no electrical power...so the hydraulic accumulators are actually charged by big dudes grinding away on manual pumps. At any given time, 5 or 6 of the 11 sailors on board are just there to power the hydraulics. If they have to tack suddenly and the accumulators aren't charged, this happens:

https://www.youtube.com/watch?v=yoOjcDf_dJA

Larry Ellison isn't talking but all estimates are that he spent somewhere between $120m and $200m of his own money defending the Auld Cup this go around. The boats themselves "only" cost around $10m in materials apiece (the Oracle program had 2) but they required a small army to build, maintain, tweak, and sail them. Next time around I expect we'll see a smaller, somewhat cheaper version of the AC72 class...but they're absolutely amazing boats, & the America's Cup stirred up a lot of interest in smaller foiling cats like the ones Timbo is posting.