Wigwam
...that the 1860 Republican and 1864 Democratic national conventions were held at the Wigwam, a building built in just over a month?
...that the <a href="./1860_Republican_National_Convention" id="mwEX8" rel="mw:WikiLink" title="1860 Republican National Convention">1860 Republican</a> and <a href="./1864_Democratic_National_Convention" id="mwEYA" rel="mw:WikiLink" title="1864 Democratic National Convention">1864 Democratic</a> national conventions were held at the <b id="mwEYE"><a href="./Wigwam_(Chicago)" id="mwEYI" rel="mw:WikiLink" title="Wigwam (Chicago)">Wigwam</a></b>, a building built in just over a month?