Aretes I have followed. A selection. An 18mm lens would have been ideal in each of these places.
East Ridge of Wolfs Head, Wyoming
Yellowspur, Eldorado Canyon, Colorado
Exum Ridge Direct, Grand Teton, Wyoming
West Ridge Bugaboo Spire, British Columbia.
Weisner Route, Bugaboo Spire, British Columbia.
Not an arete- Snake Dyke, Half Dome, Yosemite