Han dynasty watch Tower, China
This is a tower of compressed earth (soil). I would guess that this particular construction is made from adobe bricks, unburnt bricks made of earth.
This photograph illustrates quite well why I like this material and technique, it’s because its simplicity and poetic beauty. It’s constructed from the surroundings and when demolished or erroded it goes back into the ground. Dust, to dust. It is also intresting from a sustainable or ecological perspective.
Photo: By The Real Bear – Summer Vacation 2007, #263 – Watchtower In The Morning Light, Dunhuang, Gansu Province, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=7306049