【TED】Alex Honnold：我是如何爬上3000英尺高的垂直懸崖的--不用繩索 (How I climbed a 3,000-foot vertical cliff -- without ropes | Alex Honnold) (【TED】Alex Honnold: How I climbed a 3,000-foot vertical cliff -- without ropes (How I climbed a 3,000-foot vertical cliff -- without ro