This 100,000-item museum is a tour de force of Thracian and Roman artefacts, as well as icons and ecclesiastical artefacts from recent centuries. Most dazzling is the weighty Thracian gold work, part of the Panagyurishte collection, Bulgaria's biggest-ever haul of ancient gold. The museum's most arresting space is a corridor flooded with natural light, which houses Roman-era statues and mosaics. Its enormous centrepiece is a 3rd-century mosaic of a river god encircled by geometric designs.