Tokyo has mounted panels marked with QR codes on 94 trees in the central business district of Marunouchi.

Scanning a QR code with a camera phone takes you to a website that provides historical or sighseeing information about area where the tree is located. The information may tell you about the history or a nearby building or you may get information about dining and shopping in the area around the tree.

QR codes are 2-dimensional barcodes that are being used quite widely in Japan. After a QR code is photographed with a camera phone, the phone accesses the website described by the code automatically.