Ñ
Ñ, ñ is a grapheme used in Spanish to indicate the sound which in the International Phonetic Alphabet is written [nj]. It corresponds to the 'ny' in English 'canyon'. Perhaps the best known Spanish word in the English-speaking world that has this sound is 'mañana', 'tomorrow'. The symbol is also used in the standard Latin-script transcription of Sanskrit, Pali and related languages.
Other languages also have this sound, but do not use the tilde (~) for it. For example, 'mañana' in Portuguese is 'amanhã' (where the til, as it is called in Portuguese, is modifying the 'a', not the 'n': the 'h' provides the [j] sound). In Catalan, 'ny' is used, as in the local name for Catalonia, 'Catalunya'. Italian and French use 'gn', as in 'lasagne' and 'champagne' (which has a different pronunciation from the English).