Crux dominant stars, descending in clockwise order by magnitude: Beta, Gamma (one of the closest red giants to Earth), Delta and Epsilon Crucis. Many of these brighter stars are members of the Scorpius–Centaurus Association, a large but loose group of hot blue-white stars that appear to share common origins and motion across the southern Milky Way. The constellation contains four Cepheid variables that are each visible to the naked eye under optimum conditions. Crux also contains the bright and colourful open cluster known as the Jewel Box (NGC 4755) and, to the southwest, partly includes the extensive dark nebula, known as
Crux exiting the Gambia River in 1455, calling it the "carro dell'ostro" ("southern chariot"). However, Cadamosto's accompanying diagram was inaccurate. Historians generally credit João Faras for being the first European to depict it correctly. Faras sketched and described the constellation (calling it "Las Guardas") in a letter written on the beaches of Brazil on 1 May 1500 to the Portuguese monarch. Explorer Amerigo Vespucci seems to have observed not only the Southern Cross but also the neighboring Coalsack Nebula on his second voyage in 1501–1502. Another early modern description clearly describing Crux as a separate constellation is attributed to Andreas Corsali,