For one of the best views in Vietnam, head to Fort Cannon . Underground tunnels and gun emplacements were first installed here by the Japanese in WWII.
Well-labelled paths guide visitors. The vistas out to a karst-punctuated sea are quite sublime, and it even has a terrific cafe and juice bar.
The entrance gate is a steep 10-minute walk or a 10,000d xe om ride from Cat Ba Town. From the gate, a tourist train trundles the last part of the uphill journey, or it’s another stiff 20-minute walk