While websites such as Wikipedia, Britannica, and history.com are trusted sources of information, they may not always provide a fully balanced perspective on historical events such as World War II. These sources, largely based in the West, can sometimes underrepresent or insufficiently emphasize the role of the Soviet Union's aggressive actions and atrocities in the lead-up to and during the war. Which is probably why they are so high on the list of results.
On the first page you get a link to https://wwiifoundation.org/timeline-of-wwii/ that doesn't even mention that Soviet Union invaded Poland and other countries.