Carl Hagenbeck Sr., born in 1810, sold fish in Hamburg and kept exotic animals as a sideline - seals, and once a polar bear, arriving on ships from everywhere the port reached. His son took over that side of the trade at fourteen. By the 1870s the animals were worth far more than the fish, and Carl Hagenbeck the younger, born in Hamburg on 10 June 1844, was among Europe's most prominent exotic animal dealers. He travelled the world buying stock in 1874 and opened an animal park in Hamburg the same year. When an exhibition left him holding a herd of unsellable elephants, he started a circus rather than take the loss.

Alongside the animals, Hagenbeck exhibited human beings. From 1874 he showed Samoan and Sami people, the Sami staged with their tents, weapons, sledges and a group of reindeer, presented to paying crowds as specimens of the natural world. From 1876 he toured a Nubian group across the continent. In 1880 he sent Johan Adrian Jacobsen to Labrador for the party that included Abraham Ulrikab. People were recruited under false promises, and in some cases apparently taken without meaningful consent. They were not exhibits. They were families, with names, who signed on believing something other than what they got. The Labrador group was shown in Hamburg from 2 October, then Berlin, Prague, Frankfurt, Darmstadt, Krefeld and Paris. Nuggasak died on 14 December 1880, Paingu on 27 December, Sara on New Year's Eve, Maria on 10 January 1881, Tigianniak on the 11th, Tobias and Abraham together on the 13th, and Ulrike on the 16th. Their remains ended up in museum collections in Paris and Berlin, where they still are, while the Nunatsiavut government works to bring them home.

The shows lost their pull as photography spread and his tableaux began to look staged by comparison, so he set about making his displays more convincing - and that pursuit of realism is what changed zoos. In the 1890s he built the Northern Panorama: seals and walruses in a pool at the front, a moat concealed behind them, reindeer beyond it, a second hidden moat, and polar bears beyond that. To a visitor at the rail it read as one continuous Arctic landscape. He patented the idea in 1896. The engineering came from the circus: he had years of measurements on how high and how far different species could jump, so he knew exactly how wide a ditch had to be.

On 7 May 1907 Hagenbeck opened a whole park built on the principle, at Stellingen beyond the city limits, where the Tierpark still stands. Nothing was behind bars. He argued that animals from warm climates did not need the expensive, stifling glasshouses zoos had been putting them in. He called it an animal paradise where creatures would live beside one another in harmony and the struggle for survival would be abolished. The design travelled: he laid out Rome's zoo the same way in 1911, and in 1913 built the first monkey rock, an artificial crag ringed by a moat and populated with some two hundred hamadryas baboons. He died on 14 April 1913 of a snake bite, probably from a boomslang.

The First World War took the keepers into the army. With the military requisitioning civilian horses for the front, Hagenbeck's animals were hired out as draught power - elephants and trained bears hitched to heavy wagons, hauling coal and firewood through Hamburg. The zoo shut for two years afterwards as the German economy collapsed. In 1943 the bombing of Hamburg destroyed roughly seventy per cent of the park and killed nine members of staff along with many of the animals. In 1947 the British occupation authorities requisitioned a number of survivors as a forced loan to London Zoo. The family rebuilt anyway, and still owns and runs the place.

Post-war Stellingen produced its own small legends. In July 1956, forty-five rhesus monkeys got out and spent a memorable day in Hamburg's bathrooms and treetops before police, firemen, keepers and schoolchildren rounded them up. A Pacific walrus named Antje arrived in 1976, became the on-air mascot of the northern German broadcaster NDR from 1980 to 2001, and died on 17 July 2003 at twenty-seven; she is mounted and on display at the city's Zoological Museum. Near the centre of the park stands the Sala Thai, a traditional pavilion by the Thai National Artist Pinyo Suwankiri, built in Thailand with joinery that uses no nails, then shipped and reassembled by twenty Thai craftsmen - a gift from the Thai government in 2002. The Tierpark today covers nineteen hectares and holds around 1,400 animals of 140 species, with some 14,300 more in the Tropen-Aquarium.