<a href="https://en.wikipedia.org/wiki/World_War_I" id="mwYA" rel="mw:WikiLink" title="World War I">World War I</a>: The United States declares war on <a href="https://en.wikipedia.org/wiki/Austria-Hungary" id="mwYQ" rel="mw:WikiLink" title="Austria-Hungary">Austria-Hungary</a>.