Research Beach

Hey, it's me, Charles the Horseshoe Crab! Help, the tide flipped me over and I'm stuck on the back of my shell! Can you give me a hand?...

Great, thanks! Now, if only I could remember why I'm here - have you figured it out yet?

Stockholm           [][][][]
Osaka           [][][][][][][][]
Sydney      [][][][][][][][]    
Baltimore         [][][][][][]
Rio de Janeiro      [][][][][][]