In place of the bridge I see her shadow, and vehicles normally pass over it, but it appears no bridges!
If it helps, I'll send the settings of my pc:
Ubuntu 9.10
GNOME 2.28.1
Kernel: Linux 2.6.31.21-generic
Intel Pentium 4
1Gb Ram
Looks like you hit 'X' to enable some transparency. Hitting it again should undo that. With 'CTRL + X' you'll get a sort of menu where you can configure transparency settings even more.