It offers opportunities to meet challenges that call on a variety of skills, both physical and mental; but the challenges are intrinsic to the activity and do not involve beating an opponent. In that respect, surfing is closer to hiking, mountaineering, or skiing than to tennis or football: The aesthetic experience of being in a beautiful natural environment is an important part of the activity’s attractiveness; there is satisfaction to be found in the sense of accomplishment; and there is vigorous physical exercise without the monotony of running on a treadmill or swimming laps.