The city of Naarden, a 20-minute drive from central Amsterdam, was built as what military historians call a “star fort” (as seen from the air, it is said to resemble a snowflake). The architectural interest alone is reason enough to visit, but here’s another: the Naarden Piano Festival, a showcase for musicians on the cusp of mastery and well beyond. The opening concert at the city’s 15th-century Grote Kerk, home to the Netherlands’ most celebrated performances of Bach’s St. Matthew Passion, opens with solo turns and concludes with a duo finale by Nino Gvetadze, of Georgia, who serves as the event’s artistic director, and the rising Dutch star Thomas Beijer. —M.G.