Russian bombs fall daily on Kharkiv since the invasion of Ukraine, but time stood still briefly on Saturday as a group of Ukrainian musicians moved listeners with a classical concert. Three violinists, a cellist, and a bass player delighted an audience of a few dozen people for half an hour in one of the largest subway stations in Ukraine’s second city, close to the Russian border. Underground and protected from rockets and missiles, the musicians, aged 20-35, played the national anthem and several tunes from popular Ukrainian folklore.