the main house boasted ten bedroom suites , an indoor swimming pool and spa , a state-of-the-art movie theater , a chef 's kitchen and an enormous , gabled roof terrace ( known on nantucket as a `` widow 's walk , '' because in the olden days , sailors ' wives used to climb up to their rooftops and gaze out to sea , hoping to spot their husbands ' long-lost ships returning ) .