Letters from an old historian

An old University professor in the department of Art History and Antiquities has sent you a letter acknowledging your expertise in the field of Art History, requesting your help to find the Holy Grail. He has reason to believe that the Holy Grail has been hidden somewhere near the headquarters of the Secret Service and access to it could prove to be catastrophic for humankind. Therefore, he wants to get to it before anyone else does to prevent the abuse of power that will result from its discovery. He believes that someone has planted clues within Da Vinci’s most famous paintings about the exact location of the Holy Grail and needs your help to uncover them and discover its hiding spot. Solve the puzzles that pertain to Leonardo Da Vinci’s artwork to produce the coordinates that will help the professor locate and destroy the Holy Grail. Can you make it before the Secret Service gets to it? You have 50 minutes!