 The police force Guardia Civil runs controversial barracks there (works for new housing are underway).Altza (Basque for alder tree) is the easternmost district of San Sebastián along with Bidebieta and Trintxerpe.It was but a quaint village comprising scattered farmhouses and a small nucleus a century ago (2,683 inhabitants in 1910), yet on the arrival of thousands of immigrants in the 1960s and 1970s a rapid and chaotic housing and building activity ensued, resulting in a maze of grey landscape of skyscrapers and 32,531 inhabitants crammed in them (data of 1970), the figure is 20,000 .