From the WashPost: Why your favorite bench might be there to thwart a terrorist attack. An excerpt:

The goal, designers say, is to secure open spaces in a way that’s obvious enough to ward off potential attackers but, unlike standard bollards and concrete barriers, attractive enough that passersby and people using the area won’t notice. If you’ve never considered that the flowering planter where you sit on your lunch break might be strategically positioned to stop a vehicle, then they’ve succeeded.