Children watch the detection of a drug-sniffing dog at the Guangzhou Customs in Guangzhou, capital of south China's Guangdong Province, June 24, 2018. The Guangzhou Customs and the Guangzhou No. 2 Children's Palace on Sunday jointly held the open day activity for children to get to know the fight against drug trafficking. (Xinhua/Liang Xu)
A child tries to touch a detection dog at the Guangzhou Customs in Guangzhou, capital of south China's Guangdong Province, June 24, 2018. The Guangzhou Customs and the Guangzhou No. 2 Children's Palace on Sunday jointly held the open day activity for children to get to know the fight against drug trafficking. (Xinhua/Liang Xu)
A child takes a selfie with a detection dog at the Guangzhou Customs in Guangzhou, capital of south China's Guangdong Province, June 24, 2018. The Guangzhou Customs and the Guangzhou No. 2 Children's Palace on Sunday jointly held the open day activity for children to get to know the fight against drug trafficking. (Xinhua/Liang Xu)
Children watch the detection of a drug-sniffing dog at the Guangzhou Customs in Guangzhou, capital of south China's Guangdong Province, June 24, 2018. The Guangzhou Customs and the Guangzhou No. 2 Children's Palace on Sunday jointly held the open day activity for children to get to know the fight against drug trafficking. (Xinhua/Liang Xu)
Children watch the detection of a drug-sniffing dog at the Guangzhou Customs in Guangzhou, capital of south China's Guangdong Province, June 24, 2018. The Guangzhou Customs and the Guangzhou No. 2 Children's Palace on Sunday jointly held the open day activity for children to get to know the fight against drug trafficking. (Xinhua/Liang Xu)
Children watch the detection of a dog at the Guangzhou Customs in Guangzhou, capital of south China's Guangdong Province, June 24, 2018. The Guangzhou Customs and the Guangzhou No. 2 Children's Palace on Sunday jointly held the open day activity for children to get to know the fight against drug trafficking. (Xinhua/Liang Xu)