There is some very interesting history to be learned from the YIVO archive. On the left is martyr's grave in front of a fence, a victim of Chmielnicki's Cossacks, murdered in the uprising of 1648, and buried along the road by the synagogue in Tomaszow Lubelski. The center photo is the grave of an engaged couple, also murdered in the uprising, beneath a window of the synagogue, photo credit to Swarcbier, S. The photo on the right shows part of the exterior of a brick building with the inscription in Yiddish, "A structure built over the mass grave of a 'melamed' and 400 children, murdered by B. Chmielnicki's Cossacks in the uprising of 1648.
The Jewish Encyclopedia entry explains that semi-military bands of Cossacks organized themselves into armed bands and roamed the country-side. Over 500,000 Jews were murdered or died of the plague, and over 300 Jewish communiites were massacred and sacked. Jewish women were forcibly baptized and given to Cossack husbands. In one town, the article relates "[t]hree rabbis, Eliezer, Solomon, and Ḥayyim, urged their brethren not to change their religion; and about 1,000 Jews who remained steadfast were tortured and executed before the eyes of the Polish nobles (June 24, 1648). Ten rabbis were spared by the Cossacks in order to extort large ransoms from their communities."