have studied the static stress forces of the groin vault design and validated the Romans' foresight in an efficient design to accomplish the multiple goals of minimum materials use, wide span of construction, ability to achieve lateral illumination, and avoidance of lateral stresses. A seminal modern design is the largest European train station, Hauptbahnhof in Berlin, which features an entrance building with a glass-spanned groin vault design. Comparison with other vault designs The construction of a groin vault can be understood most simply by visualising two barrel vault sections at right angles merging to form a squarish unit. The resulting four ribs convey the stress loading to the four corners, or piers. The more complex groin vault is intrinsically a stronger design compared to the barrel vault, since the barrel vault structure must rest on long walls creating less stable lateral stress, whereas the groin vault design can direct stresses almost purely vertically on the piers. A common association of vaulting in cathedrals of the Middle Ages involves a nave of barrel vault design with transepts of groined vaulting. Rib vaults resemble groin vaults but introduce structural ribs running along the angles which carry much of the weight, making possible much greater variations of proportion. Examples Baths of Caracalla, Rome, Italy, early 3rd century AD 32.9 meter high groined structure Charlemagne's Palatine Chapel in Aachen, Germany Santa Maria Maggiore di Firenze, Florence, Italy, 11th-century church Basilica of Sant'Ambrogio, Milan, Italy Old Cathedral of Coimbra, Coimbra, Portugal, lateral aisles, 12th century Muchalls Castle, Scotland, ground floor rooms from the 14th century All early Russian palaces, including the Palace of Facets (1487–91) Church of St. Triphon at Ivan III's suburban estate of Naprudnoe, near Moscow, 1490s Three churches of the Rostov kremlin, 1670s and 1680s Exchange and Provost (Provost Dungeon), Charleston, South Carolina, 1771 New Orleans Mint, New Orleans, Louisiana, 1838 Aztec Center San Diego State, San Diego, California, 1968 now demolished. Basilica Minore de San Sebastián in Quiapo, Manila, Philippines. See also List of architectural vaults Tower house Steinmetz solid References External links Arches and vaults it:Volta a crociera