- Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth’s crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx “lime”, which was obtained from heating limestone.
- Wells Fargo Center (Minneapolis) (Wikipedia)
The Wells Fargo Center (90 South 7th St), formerly known as Norwest Center, is the third-tallest building in Minneapolis, Minnesota, after the IDS Center and the Capella Tower. Completed in 1988, it is 774 feet (236 m) tall. For many years, this was believed to be one foot shorter than Capella, but that structure actually had a different height (see the Capella Tower article for details). Norwest Center was designed with a modernized art deco style by César Pelli, reflecting nearby structures such as the nearby CenturyLink Building and the Foshay Tower, which is several blocks away. It is also considered by many to be a homage to 30 Rockefeller Plaza in New York City.