- Bismuth (Wikipedia)
Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs naturally, and its sulfide and oxide forms are important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery-white color when freshly produced. Surface oxidation generally gives samples of the metal a somewhat rosy cast. Further oxidation under heat can give bismuth a vividly iridescent appearance due to thin-film interference. Bismuth is both the most diamagnetic element and one of the least thermally conductive metals known.
- Indian Mounds Regional Park (Saint Paul, Minnesota) (Wikipedia)
Indian Mounds Regional Park is a public park in Saint Paul, Minnesota, United States, featuring six burial mounds overlooking the Mississippi River. The oldest mounds were constructed about 2,500 years ago by local Indigenous people linked to the Archaic period, who may have been inspired by the burial style known as the Hopewell Tradition. Mdewakanton Dakota people are also known to have interred their dead here well into that period. At least 31 mounds were destroyed by development in the late 19th century. This burial mound group includes the tallest mounds constructed by people Indigenous to Minnesota and Wisconsin (except for the unique 45-foot (14 m) Grand Mound outside International Falls, Minnesota). Indian Mounds Regional Park is a component of the Mississippi National River and Recreation Area, a unit of the National Park System…