https://en.wikipedia.org/wiki/Tiger_Stadium_(Detroit) https://en.wikipedia.org/wiki/Fenway_Park
April 20th, 1912 Grand Opening of both Detroit Stadium and Fenway Park. Detroit Park would later be renamed Tiger's Stadium and close in 1999.
Interesting that both stadiums opened on the same day, but it makes sense -- baseball's opening day. Also noteworthy that both ball parks were constructed at the expense of the team. How quaint, that a company should construct and own its place of business without forcing taxpayers to underwrite it.
Hope you'll keep this subLemmy going, thanks.