Alexandria Archive Inst
This site primarily focuses on archaeology and museum collections and is edited by professional, credentialed researchers.
However, most content is highly specialized primary field data, linked with thousands of images and some narrative documentation. While all contributions are evaluated by a credentialed editorial staff prior to publication, most content represents "field notes" and "raw data", and will likely contain some typographic and other errors. So please use with discretion.
Finally, the data in Open Context are highly portable and easy to use in "mash-ups", please see http://opencontext.org/about/services for discussion.