Two women remain missing after four people were swept into the sea on Aug. 8 at Mui Nghe, an off-limits outcrop at the eastern tip of Da Nang's Son Tra Peninsula.

Three women, all 24, slipped from the rocks that morning and were carried out by a wave. Nguyen Thai, 30, jumped in after them and was also swept away.

A fishing boat pulled Thai out at around 8 a.m. A navy vessel found one of the women more than two nautical miles offshore that afternoon, after roughly eight hours in the water.

The visitors had come to the outcrop to watch the sunrise.

Mui Nghe juts into the sea at the far eastern end of the Son Tra coastline, about 21 km from central Da Nang, and is among the first places on the peninsula to catch the sunrise.

Seen from the water it rises like a nghe, a lion-like creature from Vietnamese folklore, thus the name.

Mui Nghe in Da Nang seen from the water. Photo by Trung Dao

A vivid blue pool sits among the rocks below, filling when the tide rises or waves break over the ledge. Visitors call it the infinity pool.

Reaching it means walking 4 to 5 km through forest from the heritage banyan known locally as the thousand-year tree, on a trail that runs at 25 to 35 degrees and is thick enough with vines to disorient anyone unfamiliar with it.

The last stretch requires climbing, gripping rock or roping down a sheer drop of 70 to 100 m.

Dao Dang Cong Trung, a Da Nang tourism company director and diving instructor who has descended to Mui Nghe many times, said the terrain itself is part of the appeal for younger visitors. "On the six-level scale trekkers use, Mui Nghe rates as level 4 for danger. The rock is weathered, so it is brittle and crumbles when you grab it, while the shoreline ledges are constantly covered in slippery moss," he said.

Warning signs have stood at the descent for years.

Dinh Vui, chairman of the Son Tra Ward People's Committee, said the scenery pulls in visitors and residents alike, and photos posted on social media prompt others to follow.

Trung said approaching by small boat or stand-up paddleboard is no safer, because one current runs down from the Tien Sa lighthouse, a second flows out from Ghenh Bang and a third runs up from Cu Lao Cham, with the pattern shifting on the tide.

"The strong flow plus whirlpools at depths of 15 to 25 m is very complex, and it can drag a person far out toward a submerged reef 30 to 40 m deep," he said.

Visitors swimming in the natural pool at Mui Nghe. Photo by Trung Dao

Huynh Van Muoi, a veteran fisherman who studies weather in the waters off Son Tra, said waves there run several times higher than those close to shore when the weather turns or a southerly wind blows, and that fishing boats passing through keep at least half a nautical mile clear, about 900 m.

The ledges are covered in slippery algae and sharp oyster shells, and a visitor who falls can be cut badly enough to struggle back to shore.

"Even fishermen with decades of experience are extremely wary of this area. In the past, locals only worked along the ledges gathering seaweed or fishing for fun. Now it is mostly young people coming to take photos," Muoi said.

Roughly eight years ago, two Filipino tourists got into trouble at Mui Nghe and were rescued by a fishing boat.

A local resident who joined the search in the rain slipped, struck his head on rock and died.

Rough water at Mui Nghe in Da Nang. Photo by Trung Dao

A representative of Son Tra Peninsula and Da Nang Tourist Beaches Management Board said Mui Nghe is not a licensed site and falls outside the board's remit, and that the board has worked with local authorities for years to post signs and barricade the informal paths down, only for visitors and anglers to pull the barriers apart.

The board has asked rangers to step up patrols and fine anyone trespassing on restricted forest land.

Vui said Son Tra Ward is working with rangers to tighten control of the trails and keep people from descending into dangerous areas, Mui Nghe among them. He said local authorities have also banned unlicensed tours and are warning residents about promotional listings for them.

"We completely prohibit camping and overnight stays in this area. If any case appears, the authorities will immediately inspect and deal with it strictly," Vui said.