Get list of surrounding buildings based on coordinates from open database on Web

I would like to 开发者_如何转开发get a list of well-known buildings(museums, castles etc..) within X meters radius of the current coordinate. I would like to query them in PHP.

Do you know any such database that can be queried?

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GeoNames:

The GeoNames geographical database covers all countries and contains over eight million placenames that are available for download free of charge.

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Google Places should do well. As far as I know, open developer beta has already been released (and since it's open I'm quite sure it's stable enough).