Tisha B’Av Kinnot
The most famous author of kinnot and liturgical poetry is Eleazar Kalir, who is known by many different names. Although we don't know much about him, the story goes that, since he was such a good poet, his teacher Yannai, the other famous Eretz Yisraeli poet, actually poisoned him. The range of sources that Kalir draws from is extreme, as R. Elie Kaunfer demonstrates in this teaching.
Recorded live on Tisha B'Av 5777.