Poznań Remembrance Day in Poland is held on June 28. This event in the third decade of the month june is annual.
Similar events
Seventeenth of Tammuz in Israel on June 26 (hb. שבעה עשר בתמוז - Shivah Asar B’Tammuz. Tammuz - The start of a three-week mourning period when Jews don’t have weddings because of the breach of the walls of Jerusalem leading to the Ninth of Av (Tisha. B'Av) which commemorates the destruction of both the first and the second Holy temples);