St Paul's Cathedral familiar with the unique octagonal lantern tower over the crossing of Ely Cathedral, which spans the aisles as well as the central nave, unlike the central towers and domes of most churches. Wren adapted this characteristic in designing the dome of St Paul's. In section St Paul's also maintains a medieval form, having the aisles much lower than the nave, and a defined clerestory. The most notable exterior feature is the dome, which rises to the cross at its summit, and dominates views of the City. The height of 365 feet is explained by Wren's interest in astronomy. Until the
Strasbourg Cathedral is now the premier landmark of Alsace. One can see 30 kilometers from the observation level, which provides a view of the Rhine banks from the Vosges all the way to the Black Forest. The octagonal tower as it can be seen is the combined work of architects Ulrich Ensingen (shaft) and Johannes Hültz of Cologne (top). Ensingen worked on the cathedral from 1399 to 1419, and Hültz from 1419 to 1439. In 1505, architect Jakob von Landshut and sculptor Hans von Aachen finished rebuilding the Saint-Lawrence portal (Portail Saint-Laurent) outside the northern transept in a markedly post-Gothic, early-Renaissance style.