The interior of this building is the most beautiful I have ever seen. You shouldn’t miss it as long as you’re there. If you go to the main building first, be sure to walk through the tunnel to the library as you can skip the second security check. Without a library card, you cannot enter the library's "reading room" but there is a balcony on the second or third floor where you can look inside from above (though it is made of glass, but safe).