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Tiahuanaco, Tiwanaku

Modern scholars prefer Tiwanaku, which they consider a more accurate transliteration of the Quechua word than the traditional spelling, Tiahuanaco.

If the modern spelling is used, it should be explained, or the old spelling given in parentheses on the first mention:
            a neighboring kingdom in Bolivia, Tiwanaku (Tiahuanaco).