Marienburg fortress of the Teutonic Knights in East Prussia (now Malbork Castle in Poland). Initially water was drawn from the River Weser and filtered through sand; it was pumped into two storage tanks on the upper floor, with the turrets housing chimneys for the steam pumps, piping and access. The shape of the building led to the nickname umgedrehte Kommode (upside-down commode); the turrets have been shortened because of the danger of bricks falling from them. The tower has been protected as an architectural monument since 1978. Since the waterworks are no longer in service, the tower is to become the centrepiece of a projected residential development. Nordwestdeutsche Gewerbe- und Industrieausstellung (1890), chief designer for the largest German exposition up to that time, held jointly on 37.5 hectares of grounds in the southern part of the Bremen Bürgerpark by the Free Hanseatic City of Bremen, the Grand Duchy of Oldenburg and the Prussian Province of Hanover. Dissatisfied with the competition entries received from architects hoping to design the main buildings, the committee instead commissioned Poppe, at the time the most popular architect in Bremen, for the six main exhibit halls and the Festival Hall. These were built in only seven months, at a cost of approximately 500,000 Gold marks. All were timber, in a historical style with Baroque and Renaissance elements. After the exhibition closed in October 1890, they were demolished except for the Festival Hall, which was renamed the Park House. It was destroyed by fire in 1907, and the five-star Parkhotel Bremen now occupies the site. City Library (since 1927 State Library) (1896) Poppe won the contest to design the building against 34 other entrants. Poppe's building was heavily ornamented, but employed a modern layout in the stacks, with metal shelving and stepladders rather than floor divisions for minimal fire risk and maximum visibility. It was heavily damaged in the Second World War and eventually renovated and enlarged in a simplified form with a flat roof. In 1974 it was replaced by a modern building on the campus of the university; it was the home of the Übersee Museum Bremen until 1989, when it was demolished to build a multi-screen cinema. Bremen Cotton Exchange (1900–02) on the southeast corner of the Marketplace. Poppe won the contest to design the building in summer 1898 against 53 other entrants. His building, which cost 4.3 million marks, had a tall, ornate