The most commercially successful Spanish singer of all time, Alejandro Sanz earned a reputation as an industrious hitmaker in his native country during the '90s. By the decade's end, he'd expanded his fan base internationally as he broadened his style and began collaborating with fellow Latin superstars. On his latest album, El Tren de los Momentos (2006), he did a passionate duet with Shakira, "Te Lo Agradezco, Pero No," whom he'd collaborated with the previous year on her massive Grammy-winning hit "La Tortura." Even as Sanz broadened his style over the years, he never ventured far from his strength: romantic songs, generally ballads, tinged with flamenco and sung wholeheartedly with his distinct voice.

Sanz's El Tren de los Momentos Tour hits the WaMu Theater at Madison Square Garden on January 25.