ETHIOPIA // Forget Virgin Galactic or the Mars One mission - you don't need to leave Earth to find another world. Simply board an Ethiopian Airlines flight and make your way to Mekele before starting your descent into the surreal depths of the Danakil Depression. With fumaroles spewing sulphurous gases, boiling pools of fluorescent brine and air temperatures often exceeding 50°C (122°F), this is somewhere to visit on a well-planned expedition. You'll plunge more than 100m (328ft) below sea level and find yourself at the heart of three diverging tectonic plates - this is one of the most geologically active places on the planet. Look out for lava flowing down Irta'ale Volcano, or a lake of molten rock in its crater. There are only two guarantees about an adventure here - you'll never forget it, and you'll sweat like there's no tomorrow.