Most of us deal with escalators all the time - at work, shopping, going out for fun - and while they're a tremendous convenience, don't really think twice about them. But in one major city of South America, they have changed countless lives and helped make large areas safer and more liveable.
Most of you no doubt recall that not so many years ago, Colombia's second largest city was mired in crime and violence fueled not just by the kind of poverty found all over Latin America but also
