“If I rest, I rust,” is the catchphrase of the frequently performing Placido Domingo. Taking in the Palau de les Arts in Valencia, followed by Berlin in April, this is a European leg of the legendary Spanish tenor’s tour. Known for his powerful, versatile voice, he has sung an astonishing 144 roles in his career so far. In 2009 he proved his versatility by taking on one of Verdi’s most demanding baritone roles, the title role in Simon Boccangera, which he will play again this year in Spain and Germany.  Domingo is also a conductor, and is the general director of the Los Angeles Opera. Following his concerts in Europe, he then continues his tour in North America, arriving in Los Angeles in mid May.