Sinkhole divers. Some of the most spectacular are the Zacatón cenote in Mexico (the world's deepest water-filled sinkhole), the Boesmansgat sinkhole in South Africa, Sarisariñama tepuy in Venezuela, the Sótano del Barro in Mexico, and in the town of Mount Gambier, South Australia. Sinkholes that form in coral reefs and islands that collapse to enormous depths are known as blue holes and often become popular diving spots. Large and visually unusual sinkholes have been well-known to local people since ancient times. Nowadays sinkholes are grouped and named in site-specific or generic names. Some examples of such names are listed below. The
A Void constraint to the original, avoiding the most commonly used letter of the alphabet. This precludes the use of words normally considered essential such as "je" ("I"), "et" ("and") and "le" (masculine "the") in French, as well as "me," "be," and "the" in English. The Spanish version contains no "a", which is the second most commonly used letter in the Spanish language (first being "e"), while the Russian version contains no о. The Japanese version does not use い ("i") at all. "A Void"'s plot follows a group of individuals looking for a missing companion, Anton Vowl. It is in part