A 5000 years old Signboard with undeciphered Indus Script found at Dholavira site of Indus Valley Civilization in Kutch, Gujarat. It is the oldest known 'signboard' in the world.

• One of the most exciting discoveries at Dholavira is a large wooden "signboard" just outside the north entrance to the citadel.
• This is actually one of the longest Indus inscriptions known.
• There are 10 symbols in the panel, each one is about 37 centimetres high and the board on which the letters were inscribed appears to have been about 3 meters long. One of the symbols is repeated 4 times.
• The symbols are made of white gypsum used like mosaic tiles, attached to a wooden background. At some point the wooden sign fell face down in the dirt, eventually rotting away but leaving the bricks in place in the ground. 

• Based on its location near the gate, this large inscription has been called a "sign board," suggesting that ancient Indus gateways, or at last this one, could have had some sort of signs associated with it that visitors to the city saw before or as they entered. However until the Indus script is deciphered, what the sign is saying still remains a mystery.