- M-type star (Wikipedia)
Class M stars are by far the most common. About 76% of the main-sequence stars in the solar neighborhood are class M stars. However, class M main-sequence stars (red dwarfs) have such low luminosities that none are bright enough to be seen with the unaided eye, unless under exceptional conditions. The brightest-known M class main-sequence star is Lacaille 8760, class M0V, with magnitude 6.7 (the limiting magnitude for typical naked-eye visibility under good conditions being typically quoted as 6.5), and it is extremely unlikely that any brighter examples will be found.
- Lake Baikal (Wikipedia)
Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia, between the federal subjects of Irkutsk Oblast to the northwest and the Republic of Buryatia to the southeast.