To put it bluntly, if you have the money, we have the contacts. 

Do you want a private visit of Istanbul's Santa Sophia? We can make it happen. 

You want a private viewing of the Sistine Chapel? We just need to know in advance. Would you like to look out over Paris from the medieval bell towers of Notre Dame Cathedral? No problem, you will just have to get up a little early. 

The point is, after 25 years of creating customized tours for clients we have developed contacts all over Europe who can open doors that are usually closed. If we don't have access to something, we usually know someone who knows someone who has the key. Very often, the key needs to paid for, and depending on the venue it can be very expensive indeed, but when you need to pay for the whole security staff of the Santa Sofia to work 30 minutes overtime, it is understandable. However, more often than not, it is the little old lady who lives in the farm house around the corner who has the key to the amazing 11th century frescoed chapel that we have seemingly stumbled upon. You wouldn't know, unless you knew!