One issue with this monument is the huge amount of varying stories surrounding it. The general consensus is that a cross was built around 200 years ago by the Catholic church. The church believed this was a way to "claim the hill for the Lord."
Sometime later (locals say from a week to 100 years), lightning struck the cross causing the upper portion to topple over the cliff-side. The locals believed this to be their gods reclaiming the hill and it has been worshiped this way ever since.
Today, daily pilgrimages are made to the top to worship and make sacrifices. As you climb the hill to the top one thing to notice is the large amount of burnt rock. Very often people bring candles to burn and pray around.
If visiting, be respectful. This is a place of worship, and while photos are allowed do be subtle about it. In addition, be careful. The climb up is filled with sharp boulders and many cacti. Bring proper hiking shoes to make the climb, and be sure to bring lots of water. It may not seem like a long hike, but the Haitian sun is quite dehydrating.