I remember learning that many of the famous gravesites in Israel- the Rambam, Dan of the 12 tribes, Rav Shimon Bar Yochai, Ruth from Megillas Ruth (not necessarily these exact ones, just giving examples)- were revealed by the Arizal.
(this is also mentioned on his Wikipedia page, 2nd paragraph in this link).
Have a few questions:
a) how do we know this? (ie source)
b) how did he do it? (ie what methods did he use to uncover these locations)
c) how did this become a (pretty much) accepted fact- so much so that we built giant matzeivot and areas for people to visit for each of these tzaddikim?