Oil refinery. This is a vacuum pipestill, a distillation tower (still) where the high-boiling point part of crude oil is refined into parts (fractions) such as fuel oil and bitumen. The crude oil, a mixture of hydrocarbons, is heated to around 400 degrees Celsius and piped into the bottom of this tower in a vacuum. This lowers the boiling point of the fractions. Hydrocarbon gases from the boiling oil rise up the tower towards the coolest area at the top. Different fractions are collected at different levels, depending on their boiling point. Fuel oil is collected at a higher level than bitumen. The low-boiling point part of crude oil is refined earlier in an atmospheric pipestill. Photographed at ExxonMobil's Fawley Oil Refinery, Hampshire, UK.