Charles V Wall
... that the Charles V Wall was built by Spain to keep the Barbary pirates out of Gibraltar, but ended up being used by the British to keep the Spanish out?
... that the <b id="mwC-8"><a href="./Charles_V_Wall" id="mwC_A" rel="mw:WikiLink" title="Charles V Wall">Charles V Wall</a></b> <i id="mwC_E">(pictured)</i> was built by <a href="./Spain" id="mwC_I" rel="mw:WikiLink" title="Spain">Spain</a> to keep the <a href="./Barbary_pirates" id="mwC_M" rel="mw:WikiLink" title="Barbary pirates">Barbary pirates</a> out of <a href="./Gibraltar" id="mwC_Q" rel="mw:WikiLink" title="Gibraltar">Gibraltar</a>, but ended up being used by the <a href="./United_Kingdom" id="mwC_U" rel="mw:WikiLink" title="United Kingdom">British</a> to keep the Spanish out?