In July of 2005 my husband went to London for a few weeks.  He was doing research for a college art class he would later be teaching.  The first day he was there the 7/7 bombings occurred.  The bombings targeted public transportation.  He was scared.  I was wigging out!  He spent the rest of the trip going everywhere on foot.  He walked and walked and walked.  He wore his shoes out, got many blisters, but he was safe.  And he saw much more of London that way; the nooks and crannies of the city that you only experience by chance while walking down an alley or stopping to look at graffiti art or noticing the curiosities of passers by.