As you look at the majestic Crater Lake, located in south-central Oregon, United States, it is hard to imagine that thousands of years ago this place was one giant crater with scorching hot lava spilling over the sides. Those were the times of turmoil. Now, however, this place is the essence of tranquility. The lake that was formed, after the volcano died down, is amazingly clear due to the fact that the water isn’t moving at all. No rivers go in or out of the Crater Lake, and the water lost through evaporation is compensated by the rain and snowfall. This lake is also frighteningly deep – 1,943 feet (592 m) at its deepest point – making it the deepest lake in the United States. If you love nature and if you ever come to Oregon, this is truly a sight to behold.

Kelimutu is a volcano, close to the small town of Moni about 50 km to the east of Ende, Indonesia in central Flores Island of Indonesia.

Lake Assal is a crater lake in central-western Djibouti. It is located at the western end of Gulf of Tadjoura in the Tadjoura Region, touching Dikhil Region, at the top of the Great Rift Valley, some 120 km (75 mi) west of Djibouti city. Lake Assal is a saline lake which lies 155 m (509 ft) below sea level in the Afar Triangle, making it the lowest point on land in Africa and the third-lowest land depression on Earth after the Dead Sea and Sea of Galilee.

These are the ambitious plans which suggest skyscrapers of the future may house an entire city. The Endless City project is an award-winning proposal by sure Architecture, who propose turning skyscrapers into complete ecosystems. London is the proposed city for the mixed-use tower – which would feature huge ramps linking different sections of the structure. The company, whose design won the SkyScrapers and SuperSkyScrapers Competition, insist the structure would be a great space-saver in dense cities which have previously spread outwards rather than upwards. (Photo by Caters News)

A man sleeps between tombstones in front of his single-room home on a hot night in the Cairo Necropolis, Egypt, October 13, 2015. In the sprawling Cairo Necropolis, known as the City of the Dead, life and death are side by side. Amid a housing crisis in Egypt, and with the population of greater Cairo estimated at about 20 million, people count themselves lucky to have a place to call home in the graveyards that date back hundreds of years. (Photo by Asmaa Waguih/Reuters)

Kale grows at Kajodlingen farm in Gothenburg, Sweden, September 28, 2016. They are doing it on the rooftops, on tower block balconies and even on a disused railway: Swedes have discovered a passion for urban gardening as a way of growing fresh food and getting back in touch with nature. Part of a global movement, an increasing number of Swedish city-dwellers are growing their own in window boxes and allotments or are visiting public gardens built in or on industrial or office spaces. (Photo by Maxim Shemetov/Reuters)