- Crimea (Wikipedia)
Crimea (/kraɪˈmiːə/ kry-MEE-ə) is a peninsula in Eastern Europe, on the northern coast of the Black Sea, almost entirely surrounded by the Black Sea and the smaller Sea of Azov. The Isthmus of Perekop connects the peninsula to Kherson Oblast in mainland Ukraine. To the east, the Crimean Bridge, constructed in 2018, spans the Strait of Kerch, linking the peninsula with Krasnodar Krai in Russia. The Arabat Spit, located to the northeast, is a narrow strip of land that separates the Syvash lagoons from the Sea of Azov. Across the Black Sea to the west lies Romania and to the south is Turkey. The population is 2.4 million, and the largest city is Sevastopol. The region has been under Russian occupation since 2014.
- Rubidium (Wikipedia)
Rubidium is a chemical element; it has symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density higher than water. On Earth, natural rubidium comprises two isotopes: 72% is a stable isotope 85Rb, and 28% is slightly radioactive 87Rb, with a half-life of 48.8 billion years – more than three times as long as the estimated age of the universe.
