Tightly woven around spectacular architecture, verdant parks and abundant retail, it’s no surprise that the pavements of Manhattan rate as the US’s most well trodden. But city-builders across the country are now casting their gaze to Denver as it emerges as the US’s second most “walkable” city. The findings come from a recent report and arrive at a time when the country’s smaller downtowns are increasingly becoming dead spaces devoid of activity; a lack of pedestrians owing to a lack of places to shop, socialise and the like.So what did Denver do to buck this trend? Smart investment in mixed-use developments in its CBD has created a concentration of jobs (and foot traffic) downtown; employment has grown 30 per cent from a decade ago, in fact. Public-transport links have improved too, seeing more workers swap cars for greener commutes that involve a few more footsteps and a little less depletion for the planet and their pockets.Creating a vibrant, compact downtown is not easy: it involves being smart with density and designing on a human scale. But do it right, as Denver has, and you'll create a fitter, happier and more productive city – well worth the effort, we say.