Stratobowl
... that the first high-altitude balloon flight from Stratobowl attracted 30,000 spectators?
... that the first <a href="./High-altitude_balloon" id="mwASE" rel="mw:WikiLink" title="High-altitude balloon">high-altitude balloon</a> flight from <b id="mwASI"><a href="./Stratobowl" id="mwASM" rel="mw:WikiLink" title="Stratobowl">Stratobowl</a></b> attracted 30,000<span id="mwASQ" typeof="mw:Entity"> </span>spectators?