How many art museums invite you to see great works of art, free of charge? How many of them have smiling guards who welcome guests as graciously as the Timken's? This jewel-like repository houses the Putnam Foundation's collection of 19th-century American paintings and works by European old masters, as well as a worthy display of Russian icons. Yes, it's a small horde, but the marquee attractions include a Peter Paul Reubens, Portrait of a Young Man in Armor; San Diego's only Rembrandt, St. Bartholomew; and a masterpiece by Eastman Johnson, The Cranberry Harvest. You'll find a spot apiece for works by Bierstadt, Pissaro, Corot, and Cézanne. Since you can tour all of the museum in well under an hour, the Timken also makes for an easy introduction to fine art for younger travelers (pick up a copy of the Children's Gallery Guide for $2). Docents are available Tuesday from 10am to noon and 1 to 3pm; Wednesday and Thursday from 10 to noon; or by appointment.