The port city of Quanzhou is once hailed by Italian explorer Marco Polo as a "great city". (Photo: Shutterstock)

Located on narrow plains along the coastline of Fujian province, Quanzhou was one of the world's largest ports along the historic Maritime Silk Road, particularly in ancient China's Song Dynasty (960-1279) and Yuan Dynasty (1271-1368).

The properties in Quanzhou include 22 sites of administrative buildings and structures, religious buildings, and statues across the city. The properties were  home to multi-cultural communities, cultural memorial sites and monuments, the production of ceramics and iron, and a transportation network formed from bridges, docks and pagodas that guided voyagers.

Meanwhile, construction of Ramappa Temple, a sandstone Shiva temple in India, began in 1213 and is believed to have continued for over some 40 years.

The 1.4-kilometer-long trans-Iranian Railway connects the Caspian Sea in the northeast with the Persian Gulf in the southwest, crossing two mountain ranges as well as rivers, highlands, forests and plains, and four different climatic areas.

Started in 1927 and completed in 1938, the railway is notable for its scale and the engineering work it required to overcome steep routes and other difficulties.