Around town, furnaces are gobbling up fuel to heat buildings and keep occupants warm.But 55 downtown buildings share a hidden secret: cheap heat from deep beneath the earth.

• 但是，波塞市区的55栋建筑物，其中包括一家新的旅馆，都有一个共同的秘密，那就是：它们的暖气来自地下，而且费用低廉。