The Messenger of Allah ﷺ visited his mother's grave and wept and cause those around him to weep. The Messenger of Allah ﷺ then said: I asked my Lord's permission to pray for forgiveness for her, but I was not allowed. I then asked His permission to visit her grave, and I was allowed. So visit graves, for they make one mindful of death. (Using translation from Abū Dāʾūd 3234)
زَارَ رَسُولُ اللهِ ﷺ قَبْرَ أُمِّهِ فَبَكَى وَأَبْكَى مَنْ حَوْلَهُ فَقَالَ اسْتَأْذَنْتُ رَبِّي فِي أَنْ أَسْتَغْفِرَ لَهَا فَلَمْ يَأْذَنْ لِي فَاسْتَأْذَنْتُهُ فِي أَنْ أَزُورَ قَبْرَهَا فَأَذِنَ لِي فَزُورُوا الْقُبُورَ؛ فَإِنَّهَا تُذَكِّرُكُمُ الْمَوْتَ