Students walk through the campus of the Shanghai Tech University in the Zhangjiang Hi-Tech Zone.

Students walk through the campus of the Shanghai Tech University in the Zhangjiang Hi-Tech Zone.

Students walk through the campus of the Shanghai Tech University in the Zhangjiang Hi-Tech Zone.

The skyline seen from an airplane through heavy smog.

Residential buildings seen from the Yalong Bay Mangrove Tree Resort, operated by Antaeus Group.

Motor scooterists wait at a traffic signal.

Adventure tourists take a guided tour on the exterior of the Jinmao Tower seen from the Shanghai World Financial Center (SWFC).

Tourists walk past a propaganda banner.

A woman walks on the North Korean side of the border fence in the town of Hyesan, seen from across the border in Changbai.

Tourists ride on a ferry crossing the Huangpu River towards the Lujiazui Financial District.

A woman walks on the North Korean side of the border fence in the town of Hyesan, seen from across the border in Changbai.

The skyline seen from an airplane through heavy smog.

A soldier walks on the North Korean side of the border fence in the town of Hyesan, seen from across the border in Changbai.

A view of the town of Hyesan, North Korea, seen from across the border, formed by the frozen Yalu River, in Changbai.

A barbed wire fence running along the border crossing in the town of Changbai on China's border with North Korea.