Willi & Isolde Liebherr was born in Bulle, Switzerland, Switzerland. Willi & Isolde Liebherr is #238 in List Billionaires People In The World. Willi and Isolde Liebherr's father was one of the most revered industrialists of post-World War II Germany. Hans Liebherr recognized the need for machinery to rebuild his country while managing his parents' construction firm. With the introduction, in 1949, of the first mobile tower crane, Hans Liebherr Maschinenfabrik (Engineering Works) was born, in Kirchdorf. After unveiling the first hydraulic excavator in Europe, in 1953, Hans branched out into appliances, aerospace components and systems, concrete mixers, machine tools, material-handling equipment, diesel engines and climate-control technology. When Hans died in 1993, at age 78, his company had become one of the largest equipment manufacturers in the world. Management control then passed to Willi -- who joined the business in 1971, after earning a mechanical engineering degree from the Federal Institute of Technology in Zurich -- and his sister, Isolde, who joined the business in 1976 after earning a degree in management from the Business School of Mannheim (Germany). They continued to expand the business and eventually, their children assumed management positions within the company. Willi's son Jan shares management responsibility with his father for separate divisions focused on earthmoving machinery and components (diesel and gas engines, fuel-injection systems, hydraulic cylinders, gearboxes, winches, etc.), while sister Sophie Albrecht likewise shares management responsibility with Willi for the mobile cranes and mining divisions (the latter includes equipment such as hydraulic excavators weighing up to 880 tons). Isolde's daughter Stéfanie Wohlfarth shares management duties with her mother for the appliances division and her uncle Willi for the tower cranes company area. Sister Patricia Ruef presides over the maritime cranes division with her mother, while also sharing responsibility with Willi for the machine tools and automation systems division. Today, the Liebherr Group, which also owns six luxury hotels in Ireland, Austria and Germany, employs more than 40,800 people in over 130 companies at sites on every continent (aside from Antarctica). Its holding company, Liebherr-International AG in Switzerland, is fully owned by members of the Liebherr family.