cascading menu?

I have a wordpress based blog and I’m trying to create cascading menu similar to this site https://www.myopenuniversity.com . The menus on the wordpress blog wont be dynamic they will be link to static pages and the menu will be exactly on the same same spot on my blog as on the https://www.myopenuniversity.com . So is there any plugin or some sort of code that i can use to get the job done? thanks