Lined with pastel-coloured houses from a variety of periods, the pedestrian square is lorded over by the Gothic Stadtturm (1316). It stands next to the richly gabled Rathaus, originally two merchant's homes but repackaged in neo-Gothic style in the 19th century. Just east of the tower is the gleaming golden Dreifaltigkeitssäule (Trinity Column), erected in 1709 as a nod to Catholic upheavals during the War of the Spanish Succession.
Straubing has about half a dozen historic churches. The most impressive is St Jakobskirche, a late-Gothic hall church with original stained-glass windows; it was the recipient of a baroque makeover, courtesy of the frantically productive Asam brothers. The pair also designed the interior of the Ursulinenkirche, their final collaboration; its ceiling fresco depicts the martyrdom of St Ursula surrounded by allegorical representations of the four continents known at the time. Also worth a look is the nearby Karmelitenkirche.
North of here is the former ducal residence Herzogsschloss, which overlooks the river. This rather austere 14th-century building was once the town’s tax office.
One of Germany’s most important repositories of Roman treasure is the intimate Gäubodenmuseum. Displays include imposing armour and masks for both soldiers and horses, probably plundered from a Roman store.