So here they are, fifteen pictures of subway entrances. Yay!
If you need a clue, right below this paragraph, I've put the fifteen cities in question in a list - cleverly disguised in the colour white. They're not in order, but if you want, you can match them up with the pictures. Highlight 'em to read 'em. Otherwise, answers tomorrow!
- Hong Kong
- Los Angeles
- Sao Paulo
- Mexico City