Powers, a compact 36-year-old with a shaved head, flips off the boat's lights.

FORBES

As we head back out into the paddy fields, he lights a clove-scented cigarette and points to the shadowy, still-active volcano that shares its name with him - Gunung Agung, the tallest, most sacred mountain on Bali, from which rivers are said to flow and the volcanic soil gains its rich fertility.

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Sightings are notoriously difficult to predict and cannot be guaranteed, but if you want to chase the elusive lights, right now is the best time to head up north.

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Concerns were raised by head teachers at two large secondary schools in the area due to the number of ambulances driving past on blue lights.

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Arteaga looks to where the lights of Condado stretch below us, like flecks of glitter against the dark sky, and shakes his head.

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Others head to the top-floor deck, where small private dining rooms offer views over the river to the neon lights of Pudong, punctuated by the two-globes-on-a-stick TV Tower, the symbol of modern Shanghai.

FORBES: Escapes