Please, all the data is extracted automatically from UNESCO data.
If you want a correction - and I'm sure there may be quite a few errors - please contact UNESCO directly at http://whc.unesco.org . They are correcting coordinates from time to time.
One just simply cannot correct all the data manually.
And it would be overwritten again on the next update
After the corrected coordinates are available on the UNESCO site, let me know and I'll re-generate the Placemarks.