United States National Arboretum

The nation's capital is crammed full of buildings, streets and Metro stops but for those looking for a quiet getaway inside the district's borders, head to the United States National Arboretum. The 446-acre campus features trees, shrubs and herbaceous plants where people may observe and learn more about them. Admission is free and you can walk, drive or bike through the nine miles of roadway inside the arboretum. Here's a fun fact: scientists at the Arboretum have developed more than 650 plants through years of research. Be sure to check out the 'What's Blooming' page on their website to see what will be on full display during your visit.