Internationale Gartenbauausstellung 1963 Hamburg was the second Horticultural Expo organised under the auspices of the BIE, receiving recognition by the General Assembly on 16 November 1961. The Expo, which gathered 35 participating countries, was inaugurated by Heinrich Lübke, President of the Federal Republic, and received a total of 5.4 million visitors during its six-month run.

IGA 1963 followed a long line of international horticultural exhibitions organised in Hamburg, dating back to 1850, with the latest edition taking place in 1953. The Expo site, centred around the Planten un Blomen park (“Plants and Flowers”), was initially developed in 1938 and was also host to IGA 1953.

The city of Hamburg underwent a raft of changes ahead of IGA 1963. New water features were built in the area, a pedestrian passage was constructed under the highway in order to connect the Milertor to the Botanical Garden, which was expanded with the construction of several greenhouses designed by Bernhard Hermkes. The Wallgraben fortifications, destroyed during the Second World War, were restored, and a new bridge was built to connect the north and south parts of the area. Additionally, a play area and an elevated waterside café were built on the newly developed part of the Expo site.

Within Planten un Blomen, tropical greenhouses were built, as well as a 1.5km railway circuit and cable cars offering sights over the Expo site’s national gardens, ponds, and futuristic restaurants. Reflecting the modern era, the Expo featured a “Technology in Horticulture” exhibit, which included automated nurseries and latest-generation greenhouses.

In the historical context of IGA 1963, international participation was significant, although no official invitations were sent to socialist states in order to avoid addressing the issue of East and West Germany. International displays were found in the Halle der Nationen, adjacent to Planten un Blomen, as well as in the national gardens situated across the Expo site.

The redevelopment of the site transformed the area, which continues to be the “green lung” of Hamburg to this day. While the cable car was removed after the Expo, the railway remained in place until the site hosted IGA 1973. The greenhouses of the Botanical Garden, today known as the Old Botanical Garden, remain one of the most recognisable attractions in Hamburg.