Is it permissible for mosque imams to invite people to visit edifices and memorial monuments named after those referred to as martyrs, then to celebrate and deliver speeches, knowing that there is intermingling?

If monuments and memorial structures are erected over the grave, its visitor should emulate the guidance of the Prophet, peace and blessings be upon him, in visiting graves to supplicate for the deceased, to ask for mercy and forgiveness for them, and to say: "Peace be upon you, inhabitants of these dwellings, from among the believers and Muslims. Verily, God willing, we shall join you. We ask God for well-being for us and for you."

It must be noted that it is not permissible to build anything upon the grave, neither a monument, nor a structure, nor anything else, due to the Prophet's prohibition, peace and blessings be upon him, against plastering graves and building upon them.

As for celebrating and delivering speeches, this is an innovation and a sin, whether these structures are on the grave or not. The matter worsens if it is accompanied by corrupt practices such as intermingling. It is not permissible to invite people to such innovations nor to attend them. The Imam must call to the Sunnah (definition) of the Prophet, peace and blessings be upon him, not to innovation.