Traveling, to answer which of the two, but I prefer something simple. A night picnic for two, talking and starring at the stars, etc. The most romantic gesture would be a kiss on the forehead.
If you want to enjoy all this stuff then i guess you both should get away from your mobile phones first !
Watching reptiles(like snakes) together with your boyfriend/Girlfriend...scary though..lol!..but i like watching snakes