Casas. Formerly masked wrestlers who lost their masks, such as Satánico, Cien Caras, Cibernético and others, have had continued success despite losing their masks. Luchas de apuestas With the importance placed on masks in lucha libre, losing the mask to an opponent is seen as the ultimate insult, and can at times seriously hurt the career of the unmasked wrestler. Putting one's mask on the line against a hated opponent is a tradition in lucha libre as a means to settle a heated feud between two or more wrestlers. In these battles, called luchas de apuestas ("matches with wagers"), the wrestlers "wager" either their mask or their hair. "In a lucha de apuesta (betting match), wrestlers make a public bet on the outcome of the match. The most common forms are the mask-against-mask, hair-against-hair, or mask-against-hair matches. A wrestler who loses his or her mask has to remove the mask after the match. A wrestler who loses their hair is shaved immediately afterward." If the true identity of a person losing his mask is previously unknown, it is customary for that person to reveal his real name, hometown and years as a professional upon unmasking. The first lucha de apuestas was presented on July 14, 1940, at Arena México. The defending champion Murciélago (Velázquez) was so much lighter than his challenger (Octavio Gaona), he requested a further condition before he would sign the contract: Octavio Gaona would have to put his hair on the line. Octavio Gaona won the match and Murciélago unmasked, gave birth to a tradition in lucha libre. Variants Máscara contra máscara ("mask versus mask"): Two masked luchadores bet their masks and the loser is unmasked by the winner. This is the most prestigious match in Mexican Lucha libre since it´s a match of high reward (Unmasking a prestigious wrestler often is a major career push for the winner) but also an extremely high risk (when the unmasked wrestler´s popularity decays and it's not uncommon he/she opts for adopting another gimmick and restart his/her career, or to retire after a while) The quintessential example is the 1952 match in which El Santo gained the mask of Black Shadow (wrestler). This match is so transcendental that it established the Lucha Libre as a cultural phenomenon in Mexico. Another example occurred in the year 2000 when Villano III lost his mask to Atlantis (wrestler), which some considered the best