It's been about 13 centuries since Homer envisioned a mythical floating city surrounding by "unbreakable bronze." The idea has generally remained the province of myth since then - until last month.

What once seemed like the moonshot vision of tech billionaires and idealistic architects could soon become a concrete solution to several of the world's most pressing challenges. At a United ...

Worldwide, rising sea levels and increasing urbanisation represent a formula for disaster, with more and more people seeking to live on land that will, at some point, be swallowed up by the sea.