Athirappilly Water Falls

Athirappilly Falls is situated in Athirappilly panchayath in Thrissur district of Kerala, on the southwest coast of India. Located on the west-flowing Chalakudy River near the Vazhachal Forest Division and the Sholayar ranges, this 24-metre (80 ft) waterfall and the nearby Vazhachal Falls are popular tourist destinations. It is nicknamed "The Niagara of India". 

Forest wildlife in the area includes the Asiatic elephant, tiger, leopard, bison, sambar, and lion-tailed macaque. The unique 180 metres (590 ft) elevation riparian forest in the Athirappilly-Vazhachal area is the only location where all four South Indian species of hornbills — theGreat Hornbill (the State Bird of Kerala), Malabar Pied Hornbill, Malabar Grey Hornbill, and the Indian Grey Hornbill are found living together.

The journey from Chalakudy to the Athirappilly Falls passes through a landscape of winding roads, small villages and lush green trees. Visitors can reach the top of the waterfall via a paved path that leads through thick bamboo clusters. A steep narrow path also leads to the bottom of the falls. The falls attract visitors from across India, especially during the monsoon months (June–September). About 7 million tourists visit the falls and the Vazhachal picnic spot each year.

I think ,best time to visit is just after monsoon... :)