The Old Arsenal, built in the 16th century and restored in the 1980s, houses temporary exhibitions and a permanent collection showcasing 15th- to 19th-century Lithuanian sacred art. Many pieces were discovered in Vilnius Cathedral in 1985 after being hidden in the walls by Russian soldiers in 1655. Because of fear that they’d be seized by the Soviets, the works, valued at €11 million, remained a secret until 1998, when they were finally displayed to the world.