The first cross-boundary marathon jointly hosted by Shenzhen and the Hong Kong Special Administrative Region kicked off on Saturday morning. Starting from Shenzhen, runners in the 15th National Games event entered the SAR via Shenzhen Bay Port, with neither documentation nor stops required. The organizing committee said the marathon demonstrates the vibrancy of the athletes from across the nation and the collaborative spirit of Guangdong province and the Hong Kong and Macao SARs in celebrating the grand occasion. Click on the video for more.