Kolel L'horaah Ma'asis Crown Heights - Shiur 31 on halachic topics - by Rabbi Shraga Dovid Homnick, Sgan Rosh Kolel, on the halachos which are zecher l'churban and the debates surrounding their practice, the lomdishe parameters of zecher l'mikdash, the concept of 'Meheira Yibaneh Hamikdash,' and a postscript about the group known as the Avelei Zion

https://www.youtube.com/watch?v=dDDLzIwlgRs