It is also a popular tourist destination, and like many parts of the country faces the challenge of balancing development with environmental protection.Tenuous conservation success stories can be found here, but current and future developments in surrounding areas pose acute threats. CAT BA ISLAND, Vietnam – While approaching Hai Phong, a major city on Vietnam’s northeast coast, it is impossible to miss signs of the country’s fast-growing economic might. GDP growth hit just over 7 percent in 2018, and foreign investors are swarming: Samsung alone has invested nearly $20 billion here. A high-speed expressway now connects Hai Phong to Hanoi, the capital, and will eventually extend to the Chinese border farther north. We turned the opposite direction and rumbled down a broad road past under-construction factories and sprawling stacks of shipping containers. An enormous amount of land is being reclaimed from the sea for industrial zones advertised on billboards, while dozens of boats moored offshore pump water out of mud flats and into the Gulf of Tonkin. The 5.4-kilometer (3.4–mile) Tan Vu-Lach Huyen bridge, Vietnam’s longest cross-sea span, leads to a small island called Cat Hai, where fish farms give way to a colossal 336-hectare (830–acre) automobile and motorbike manufacturing complex run by Vinfast, a subsidiary of Vingroup, the country’s largest private corporation. Finally, we reached a run-down ferry crossing. Eight towering container cranes loom overhead, part of the expanding Lach Huyen International Port. Across a narrow stretch of water plied by huge cargo ships, a different type of skyline unfurls: the verdant, jagged limestone karsts of Cat Ba Island, a stunningly beautiful destination that attracts 2.5 million tourists a year, according to local media. The largest in the Cat Ba archipelago, which includes 365 other islands stretching into the Gulf of Tonkin, Cat Ba is home to both a national park and a UNESCO Man and Biosphere Reserve. In many ways, it is a microcosm of the major environmental issues Vietnam currently faces: wildlife conservation, forest preservation, overtourism, unchecked development, plastic waste and more. Biodiversity hotspot