The Hungarian Parliament Building consumes 40,000 light bulbs each evening, transforming the Danube's eastern bank into a neo-Gothic mirror of gold and white that has anchored Budapest boat tour night departures since the millennium restoration in 2000. The river itself divides two cities—Buda's castle hill rising to the west, Pest's commercial grid stretching east—that were formally unified only in 1873, and the night cruises that now carry 1.2 million passengers annually trace the seam where that merger occurred. Chain Bridge, completed in 1849 as the first permanent span between the two halves, inaugurated the tradition of illuminated crossings; its suspension cables now glow amber against basalt piers, a geometry repeated by Margaret Bridge to the north and Liberty Bridge's art nouveau ironwork to the south. The river corridor itself became a UNESCO World Heritage Site in 1987, and the protected zone extends from Gellért Hill's citadel south to Margaret Island's parkland north, a 5.2-kilometre stretch that contains eight bridges, three Parliament-scale landmarks, and the thermal spring outlets that have drawn settlement since Roman Aquincum. Evening vessels pass within 50 metres of the Parliament's river façade, close enough to distinguish the building's 691 individual rooms and the Gothic Revival tracery that architect Imre Steindl adapted from Westminster Palace during the structure's 1885–1904 construction. Buda Castle, perched 48 metres above the waterline on the opposite bank, anchors the western skyline; its baroque reconstruction followed the 1945 siege, and the Royal Palace now houses the Hungarian National Gallery's 100,000-piece collection, invisible from the river but defining the hilltop silhouette. Margaret Island bisects the Danube midway through the heritage corridor, a 2.5-kilometre ribbon of parkland and ruins accessible only by bridge—no vehicular traffic—where a 13th-century Dominican convent and a reclaimed water tower frame the northern turn. The timing of budapest boat tour night departures aligns with the 7:45 PM automated lighting sequence that illuminates all eight bridges simultaneously, a coordinated event installed in 2009 and sustained by the city's public works authority. Operators cluster their moorings along Duna korzó, the two-kilometre promenade that parallels Pest's riverfront between Erzsébet Bridge and Chain Bridge, where stone embankments and cast-iron bollards date to the 1870s regulation works that stabilised the channel and enabled consistent navigation.