Alan Cumming and Uma Thurman attend the Versace for H&M Fashion event at the H&M on the Hudson on November 8, 2011 in New York City. (Photo by Rabbani and Solimene Photography/Getty Images for Versace for H&M)

The Grand Canyon Skywalk is a transparent horseshoe-shaped cantilever bridge and tourist attraction in Arizona near the Colorado River on the edge of a side canyon in the Grand Canyon West area of the main canyon. USGS topographic maps show the elevation at the Skywalk's location as 4,770 ft (1,450 m) and the elevation of the Colorado River in the base of the canyon as 1,160 ft (350 m), and they show that the height of the precisely vertical drop directly under the skywalk is between 500 ft (150 m) and 800 ft (240 m).

“Huangguoshu Waterfall, also known as Yellow Fruit Tree Waterfall, is one of the largest waterfalls in China and East Asia located on the Baihe River in Anshun, Guizhou Province. It is 77.8 m (255 ft) high and 101 m (331 ft) wide. The main waterfall is 67 m (220 ft) high and 83.3 m (273 ft) wide”. – Wikipedia

Photo: The Miao ethnic minority women rest in front of Huangguoshu Cataract, Asia's largest waterfall, on September 13, 2011 in Anshun city of Guizhou Province, China. (Photo by Feng Li/Getty Images)

The Soyuz 2.1b rocket with a Fregat-M booster and meteorology and emergency communications satellite Arktika-M No 1 launches from Baikonur Cosmodrome in Baikonur, Kazakhstan on February 28, 2021. Arktika-M No 1 is the first of ten Arktika satellites to be launched by Roscosmos into orbit. (Photo by Roscomos/TASS)

Cordwood construction is a method of natural building that originated roughly one thousand years ago in Greece and Siberia. This method involves using pieces of wood that slightly protrude from the mortar, giving the walls an attractive appearance. Usually, the walls are made 12 to 24 inches thick. However, in some parts of Canada, the walls can be as thick as 36 inches. This method appeals to many people due to its ease of construction economy of resources. Cordwood Construction can be separated into two main types: mortar-insulation-mortar (M-I-M) and Throughwall. M-I-M is a more preferable and widely used choice as it allows for better insulating properties.

Tank crew standing in front of M-4 tank, Ft. Knox, Kentucky, June, 1942. (Alfred Palmer/OWI/LOC)