I recently went on holiday to Lisbon, which (like Rome) is built on seven hills. The spread of the city across this picturesquely rolling landscape provides many spectacular vantage points. One of the more popular spots to appreciate the vista with a cup of tea – or cocktail – is Park bar, which is on the top floor of a rooftop parking lot and has been turned into a hip, elevated garden terrace with 180-degree views of Lisbon.

Whilst I was enjoying watching the sun set (with a G&T in hand, naturally) it occurred to me what a great example this was of the best way to use space in crowded cities. Not only is it resourcefully located, making an asset out of what could be an awkward site; it also shows off some of the best new thinking in urban development, and is effectively a sprawling garden terrace with trees, shrubs and flower-beds ensconced on a teak deck.

Rooftop bars are spreading inexorably. It’s not just for warm-weather cities anymore! London’s cocktail culture is moving up in the world as the city wakes up to its unused rooftops.

Aside from rooftop bars, there are a number of spaces being used for alternative activities: Netil House in Hackney hosts rooftop yoga, and the roof of Rockwell House in Shoreditch comes alive with 20 inflatable hot tubs for Hot Tub Cinema – which has also winged its way west to Bristol. Outside the capital, Manchester’s Hotel Football boasts a rooftop football pitch suitable for the beautiful game, corporate events, or even your big day. Hengyang, in China, has taken rooftop spaces to new heights by building 25 luxury villas on top of a shopping centre.

Hopefully rooftops will be used more and more, as the city becomes more crowded, competition for space becomes greater, and creativity in demand to make sure we achieve a balance between growing up and growing out. With imagination and persistence, the sky needn’t be the limit!