N. Kósa Judit - Szablyár Péter: Underground Buda - Our Budapest (Budapest, 2002)

Adam Clark's masterwork - the Tunnel under Castle Hill

■ Straw italactitei in a drainage duct

10.61 metres high. It is 7.85 metres high at mid-point, and its greatest width is 9.48 metres. The Tunnel tilts at 1.8% toward the Chain Bridge (few would think that the entrance at Krisztinaváros is 6.1 metres higher than the one at Clark Ádám tér). The 82—100 centimetre thick brick walls of the horse-shoe shaped section are plastered to a height of two metres and have been covered, since reconstruction in the late 1930s, with limestone slabs. The six- metre broad road surface was originally paved with wooden blocks; increased traffic required that these be replaced first with flagstones and later with asphalt.

While the first large post-war reconstruction job was done in 1949, no major overhaul was carried out before the early 1970s. It was during the 1972—73 reconstruction that an Austrian company covered the walls with the tiles visible today.

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