Neriamangalam Bridge is First Arch bridge in South India. The Neriamangalam Bridge, built across the Periyar River, is often referred as The Gateway to the Highranges as it is on the way to the higher regions of Idukki district. Built across the Periyar river, the bridge connects the Idukki and Ernakulam districts. Neriamangalam bridge is a part of Aluva – Munnar road, which was constructed to replace the Aluva – Mankulam road completely destroyed in the floods in 1924. Neria mangalam Bridge This is the first Arch bridge in south India. The construction of the bridge started in 1924 during the reign of Sethu Lakshmi Bhai, the ruler of Travancore. Sri Chithira Thirunal Rama Varma opened the bridge for public on 2nd march of 1935. The bridge was built in the name of Sethu Lakshmi Bai.