One part of the great statistics in Project-GC are the highest und lowest elevations of Caches.
I am wondering, how it works.
For example: Last week I logged the Cache "Alter Elbtunnel"(GC3YWGY). Like the Name says, it´s a tunnel under the river "Elbe".
On the website http://www.kulturkarte.de/hamburg/31030aelbtu it says, that the tunnel is 24m under Sea Level. But on the PGC statistics it is classified with 2m above Sea Level.