By LAURIE KELLMAN SINTRA, Portugal — The doorbell to Martinho de Almada Pimentel’s house is hard to find, and he likes it that way. It’s a long rope that, when pulled, rings a literal bell on the roof that lets him know someone is outside the mountainside mansion that his great-grandfather built in 1914 as a monument to privacy. There’s precious little of that for Pimentel during this summer...