You may think of squats as booty-builders, but their benefits go far beyond your peach. They strengthen pretty much every muscle in your lower body, including your quads, hamstrings, and calves. Whether you're at home or in the gym, various bodyweight squats are easy to crank out sans equipment—and are a great way to build baseline strength before loading on the weights. In general, 30-day challenges are a great way to work on your fitness, because they give you an achievable short-term goal to keep you focused. The motivation to lose weight or get fitter is obviously no bad thing, but without something clear and defined to work towards, it’s all too easy to skip a session or two then slide back into inactivity. And of all the 30-day challenges you might try, a squat challenge is one of the best. That’s because the unweighted squat is a strong contender for the finest bodyweight exercise in town. It works almost every muscle in your lower body, hitting big muscle groups like the quads, hamstrings and glutes especially hard. The squat also improves your core strength by strengthening the muscles around your stomach and lower back, and if perchance you’re dreaming of owning a six-pack one day, firming up these other muscles with squats is an important first step towards helping the exterior abs shine.