The question mark is a punctuation mark used to indicate the end of an interrogative sentence. In Spanish, the question mark is inverted, appearing as an upside-down question mark at the beginning of the sentence and a regular question mark ? at the end. For example: Cmo ests? (How are you?)
The inverted question mark is a unique feature of Spanish orthography and is not used in any other language. It is believed to have originated in the 16th century when printers would often flip the question mark upside down to save space. The upside-down question mark has since become a standard part of Spanish punctuation and is used in both formal and informal writing.