Which company, begun by a retired minister in 1876 to make socks for lumberjacks, soon expanded into underwear?

Which singer-songwriter scored her first No. 1 pop hit in 1990 with "Vision of Love"? Begun around 1088, the university in which northern Italian city is considered the oldest in Europe? Which religion, founded around 1500 by Guru Nanak, has elements in common with Hinduism? Begun around 5,000 years ago, Stonehenge's construction belongs to which "New Stone Age" period? Which war began with Frederick the Great's invasion of Saxony and lasted from 1756 to 1763? Begun in 1173, the Leaning Tower of Pisa is clad mainly in what stone? Begun around 1503, which painting has been called the most famous portrait in art history? Begun in 1815, America's first large-scale monument to which man towers above Mount Vernon Place in Baltimore?