Climbing

Attribute: Constitution
This is the ability to scale vertical surfaces, whether rock faces or buildings, with the proper equipment. Climbing a steep slope or sheer rock face with good handholds is Moderate Difficulty Check. Climbing a sheer, mostly smooth rock face or a building wall is a Hard Difficulty Check. The above assume no specialized equipment. With climbing equipment, the difficulty level is eased One Step. Rappelling is a Standard Difficulty Check. 
An experienced climber may assist an inexperienced climber. If so, the inexperienced climber uses his or her own CON attribute as a Climbing skill.