Five hundred Pacceka Buddhas once resided in Isigili for a long time;
they could be seen entering the mountain, but once entered, there was
no more sign of them. Men, observing this, said that the mountain
swallowed up the sages and so it came by its name of Isigili.
(http://www.palikanon.com/english/pali_names/i_/isigili.htm)
Maha Moggallana Thero was meditating, while some robbers or
thieves came and attacked, later after meeting Lord Byddha
Maha Moggallana Thero died and thus attained Parinibbana here.
About Isigili Rock
http://www.palikanon.com/english/pali_names/i_/isigili.htm
Isigili Sutta
http://www.accesstoinsight.org/tipitaka/mn/mn.116.piya.html
About Ven Maha Moggallana Thero
http://www.accesstoinsight.org/lib/authors/hecker/wheel263.html#ch10
http://www.palikanon.com/english/pali_names/maha/maha_moggallana_th.htm
Relics of Ven Maha Moggallana Thero
http://www.maitreyaproject.org/en/index.html
http://www.relicsofbuddha.com/barahun/page8-1-02.htm