U-573 was a Type VIIC, the workhorse design of the German submarine fleet, laid down at the Blohm & Voss yard in Hamburg in June 1940 and commissioned a year later under Kapitänleutnant Heinrich Heinsohn. She carried an unusual honorary name. In 1941 Heinsohn arranged for the Alpine town of Landeck, in the Austrian Tyrol, to adopt the submarine under a popular sponsorship scheme, and the townspeople sent gifts and organised holidays for her crew. From then on she was "U-573 Landeck": a warship of the deep ocean, godchild to a mountain town that lay about as far from any sea as a place in Europe can. It is a small, strange kindness to set beside what these boats were built to do.

For all her menace, U-573 was not a lucky hunter. She left Kiel in September 1941, crossed into the Atlantic through the gap between Iceland and the Faroes, and ranged almost to the coast of Labrador before turning for occupied Saint-Nazaire. Her second patrol was her only real success: she slipped past the heavily defended Strait of Gibraltar into the Mediterranean, torpedoed the Norwegian steamer Hellen of 5,289 tons on 21 December 1941, then made for Pola on the Adriatic. A third sortie from Pola in early 1942 passed without incident. In four war patrols under the German flag she sank exactly one ship. Whatever the recruiting posters promised, most of her war was long grey days of empty horizon and the constant grinding fear of being found.

Being found is what ended her German career. On 29 April 1942, Lockheed Hudsons of the RAF's No. 233 Squadron caught her on the surface northwest of Algiers and worked her over with depth charges. Badly damaged, she limped north and slid into Cartagena on 2 May. International law gave a warship twenty-four hours in a neutral port to make emergency repairs before internment; Spain, quietly sympathetic to Berlin, granted three months, and the British Embassy in Madrid protested hard. Heinsohn flew to Berlin to argue for his boat, then returned by train through the French border town of Hendaye. In the end the damage was beyond three months of work, and the Kriegsmarine simply sold her to Spain, one day before the deadline expired. The crew, who had lost not a single man in combat, were interned and released in twos and threes. Heinsohn left with the last five in February 1943, took command of another boat, and was dead within months, lost with all his new crew.

Spain renamed her G-7 and set about the repairs, which took four years rather than months. The British bombs had done more harm than anyone first realised, German parts were nearly impossible to obtain in the last years of the war, and Spain's own economy was still hollow after its civil war. She was finally recommissioned in November 1947, and despite being an already outdated design she was the most modern submarine Spain owned; her fleetmates dated from the early 1930s. She had no radar and no snorkel. In 1958 a film company rented her to play a U-boat in a war picture. She served on, renumbered again, until she was decommissioned in 1970 after twenty-three years and sold at auction for about $26,500. There was talk of keeping her as a museum. Instead she was broken up for scrap, the last Type VII of her kind to sail.