6. Nanda Parbat
Where to even begin with this one. During the first season of Arrow it is revealed by Malcolm Merlyn that he had trained at Nanda Parbat. While clearly only an easter-egg for us fans, thoughts rushed through my mind. So many characters have been drawn to Nanda Parbat over the years, a training ground and shrine for the Goddess Rama. Many DC heroes and villains are drawn there over the years. Out of those characters the ones that jump out at me immediately due to Merlyn's involvement are Ra's and Sensai, two members of the League of Assassins. The League has had its presence on Arrow of the course of the last year, and looks to grow this season with Bronze Tiger joining the cast. Others that have sought out include The Question, and Rene Montoya, both of whom could easily be included in the Gotham TV series.