The lagoon itself is landscaped with wooden decks, cavernous saunas and piping hot waterfalls, with its mineral-rich waters fed by the futuristic Svartsengi geothermal plant next door.

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In the United States, solar waters heaters generally sit atop individual homes and businesses, and the hot water is seldom used for space heating.

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The maritime alternative is to sail around the Arabian Peninsula, braving the pirate-infested waters off the coast of Yemen then up through the Suez Canal past the Egyptian hot spot of Sinai where a military operation remains under way.

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