Seen below are 9 sets of photos from that site. Making the left column is a photo of each set that was taken when the lights were 'on' while on the right is a column of photos of the same place with lights turned 'off'. Now, you really have to visit www.boston.com and click on the photos (starting with the second) in order to see the fade-in-and-out effect when light transitions to darkness (you'll also see last year photos).
As for Tanzania, well, I believe TANESCO does a better job forcing us to a daily dose of the 'earth hour' such that turning off our 'vibatari' and 'kandili' on this special day wouldn't have made any difference anyway.
Click on the photos to enlarge and enjoy more at www.boston.com