Flushing River
... that marshland around the Flushing River, considered "all but worthless", was later expanded into a park used for two world's fairs?
... that marshland around the <b id="mwCbU"><a href="./Flushing_River" id="mwCbY" rel="mw:WikiLink" title="Flushing River">Flushing River</a></b>, considered "all but worthless", was later expanded into a park used for two <a href="./World's_fair" id="mwCbc" rel="mw:WikiLink" title="World's fair">world's fairs</a>?