In order to come in you will have to pay the entrace fee. Once you are in, you may take exterior photos. Interior photos are not allowed.
It is fine. I dont believe they have any photo restrictions.
Outside the gate you don't a fantastic view of the buildings or anything, but obviously you're outside so you're in public domain. If you would like to take photos either professionally or not ask at the entrance, but you'll most likely have to pay the entrance fee.
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