With fall nearing its end, shades of emerald green cast a serene glow over northern Vietnam's Trang An landscape. 

Reached in about 500 steps, the summit of Mua Mountain is an ideal vantage point to take in magnificent Trang An landscape in Ninh Binh Province.

The complex, a UNESCO world heritage site, is a spectacular landscape of limestone karst peaks permeated with valleys, many of them partly submerged and surrounded by steep, almost vertical cliffs. It boasts famed sites like Trang An ecotourism zone, Tam Coc - Bich Dong tourism zone, Bai Dinh pagoda, and Hoa Lu ancient town.

This series of photos taken by Cao Tung Lam from Ba Ria-Vung Tau Province captured the beauty of Trang An in October.

An aerial view of Tam Coc, part of the Hoa Lu limestone karst area, from the peak of Mua Mountain.

To pass through Tam Coc, meaning three caves, tourists have to travel by boat along Ngo Dong River. On the way, they will also get to visit Bich Dong Pagoda, which dates back to the 15th century.

Various vendors sell incense and fruit to those visiting the pagoda.

The price for visiting the Tam Coc-Bich Dong is VND120,000 ($5.18) for adults, and VND60,000 for children under 1.4 m. A boat tour costs a minimum VND150,000 for four.

The Trang An ecotourism zone is located at the center of the complex. Tourists to Trang An can opt for three different boat tours, each one lasting three hours and priced at VND250,000 per adult, and VND120,000 for children from one to 1.3 m. The journey is free to kids below one meter.

The signature of Trang An is its system of 50 dry and 50 water caves, dating back about 250 million years. 

The river water in Trang An remains emerald green and translucent throughout the year, except after a storm or during floods. 

Only five kilometers from the Trang An ecotourism zone lies Am Tien Cave of Hoa Lu ancient town. The spot, also known as Tuyet Tinh Coc, is located in a small valley boasting a pagoda and mountain tunnel.

At Giai Lake, Dinh Dynasty (968-980) rulers used to feed their prisoners to crocodiles.

Hoa Lu, thousands of years old, was the first capital of Vietnam in the feudal times.