United States of America
The US seems to want to dominate the world both culturally and (it seems) perhaps literally. Despite the media hype there really is a country behind it all that is worth visiting. There are many large parks in addition to large cities. Many areas are sparcely inhabited and the landscape tends to vary greatly from the plains of the north midlands to the mountains of the west and deserts of the south.
There are many places to visit but get away from the big cities to see a bit of what culture exists in a country only a few hundred years old.