This was a turning point in the history of IChO .
After the 4th IChO a representative of the host country made during the closing ceremony of the current IChO an official invitation for the next IChO and it was addressed to all participating countries .
This was a turning point in the history of IChO because after the 4th IChO a representative of the host country made during the closing ceremony of the current IChO an official invitation for the next IChO and it was addressed to all participating countries .