Philadelphia is filled with possibilities for an awesome romantic date. A couple suggestions:
Morris Arboretum in Chestnut Hill is a gorgeous place for a romantic date. This place is full of gardens, sculptures, fountains, historic buildings and there is even a model train that run through.
Zavino's on 13th Street is great for pizza lovers. This quaint restaurant offers delicious pizza and a nice selection of wines.
Magic Garden on South Street is a great place to take your significant other. From the outside it doesn't look like much, but once you walk into the maze of mosaics you'll be hypnotized for sure. You can schedule a tour or, if it suits you, they offer Magic Gardens for private events.
