Primary menu

my website In my Primary Menu I have a several options, one of which (Photos) currently has 2 sub-menu items (but will have more). I would therefore like, when user clicks on the Photos menu item it doesn't open a Photos page, but instead shows the sub-menu items (2017,2016), which, when they are pressed take you to the photos page for that year. At present I can get the the sub-menu items to show, but if you click on the Photos main-menu item it opens the Photos page - I realise I probably don't need a Photos page but I'm not sure how to get the cub-menu items to work then. I have other menu items that I want to add sub-menus to, so if I can get this fixed for the Photos option, it'll help me for other options.