San Antonio Bay
... that a secret causeway from the mainland to Matagorda Island off San Antonio Bay was hidden from Europeans by Karankawa Indians?
... that a secret causeway from the mainland to <a href="./Matagorda_Island" id="mwASQ" rel="mw:WikiLink" title="Matagorda Island">Matagorda Island</a> off <b id="mwASU"><a href="./San_Antonio_Bay" id="mwASY" rel="mw:WikiLink" title="San Antonio Bay">San Antonio Bay</a></b> was hidden from Europeans by <a class="mw-redirect" href="./Karankawa" id="mwASc" rel="mw:WikiLink" title="Karankawa">Karankawa</a> Indians?