Graben, a wide-open space which is half street and half square, is the hub of the great city of Vienna. In 1950 it was the first place to have fluorescent lighting. In 1971 it became the first pedestrian zone, and soon afterwards cafes took over for the summer months what was formerly a major thoroughfare. Graben was once the city moat around the Roman Camp, then it became the flower and vegetable market, and from the 17th c. on it was the scene of Court festivities. There are two old fountains, the Joseph Fountain and the Leopold Fountain. Both were altered many times and lead figures by Johann Martin Fischer were added in 1804. Of the many Baroque buildings that surrounded the Graben in the 18th c. only the Bartolotti-Partenfeld Palace (No.11) remains. The shop façade of the jewellers Caesar’s by Hollein has long been on the itinerary of tourists interested in art. Its polished granite slab and mass of metal pipes are reminiscent of the decorative style of a previous age. Other famous shops and boutiques are nearby. Also of interest in the Graben are the subterranean Art Nouvea toilets. They were built in 1905 by Adolf Loos and have been renovated to reveal their true glory. The cubicles are lined with wood and marble panels and have gilded fittings. In the middle of the Graben stands the famous Plague Pillar. This 21 m (70 ft) tall Baroque Pillar (also called the “Trinity Pillar”) owes its existence to a vow made by Emperor Leopold I. he swore that when the plague ceased he would pay for the erection of a pillar which would reach up to heavens. The plague of 1679 cost 75,000 Viennese their lives, other estimates even reach 150,000. the first plague pillar was erected in the same year. The construction of the definitive Plague Pillar by Matthias Rauchmiller was begun in 1681, continued after his death, which occurred in 1686, by J.B Fischer von Erlach, and completed in 1693 by Locovico Burnacini. The figure of the emperor kneeling in prayer is the work of Paul Strudel that of the Trinity was modelled by Johann Kilian of Augsburg. In 1400 a wealthy cloth merchant, Michael Menschein, had the great hall on the first floor of the house at Tuchlauben 19 (near the Graben square) decorated with frescoes depicting the Minnesänger Neidhart’s poetry. In 1715-16 the house was refashioned in the Baroque style and most of the paintings were destroyed and the rest covered with a thick layer of plaster. The frescoes were discovered by accident during renovation work in 1979 and took three years to restore. They are the oldest secular wall paintings in Vienna and an important example of popular art in the late middle ages. The walls of the 15 x 7.5m (50 x 25 ft) hall were originally completely covered; the frescoes depict typical scenes from Neidhart’s songs in the cycle of the four seasons.