"Shell structures have been constructed since ancient times. The Pantheon in Rome and the in Istanbul are well-known examples. After the Roman times the traditions of domes continued up to the 17th century. Since then they seemed forgotten. Stimulated by the newly developed reinforced concrete and the demand to cover long-spans economically and column free the shell made a comeback in the early 20th century. and Ulrich Finsterwalder designed in 1925 the first thin concrete shell of the modern era, the Zeiss planetarium in Germany. The modern era of shell construction is recognised by the trend towards greater spans and thinner shells. Guided by well-known engineers as , Eduardo Torroja, Anton Tedesko, Nicolas Esquillan, and a blooming period of widespread shell construction took place between 1950 and 1970. Shell construction suddenly vanished at the end of the 1970s, mainly caused by the high costs [relative] to other structural systems. Moreover, inflexible usability and uncertainties in the structural behaviour of shells and difficulty of proper analysis methods did not help[,] neither did the stylistic identification with the 1950s and 1960s. Today the great era of thin shells is over, however, nowadays natural free-form shapes and blobs attract more and more attention. In addition, recent developments in concrete technology have led to ultra high performance fibre reinforced concrete with revolutionary performance in tension and compression. Eventually this may lead to a revival of the thin concrete shell."