At ITB-Berlin in March 2013, ATTA's Shannon Stowell, Chris Doyle and Antonio del Rosal welcome Manfred Häupl (far left) of Germany's Hauser Exkursionen, as one of the ATTA's newest members. Hauser, led by Häupl since 1973, recently celebrated its 40th anniversary and is considered one of Europe's top adventure tour operators.At ITB-Berlin in March 2013, ATTA's Shannon Stowell, Chris Doyle and Antonio del Rosal welcome Manfred Häupl (far left) of Germany's Hauser Exkursionen, as one of the ATTA's newest members. Hauser, led by Häupl since 1973, recently celebrated its 40th anniversary and is considered one of Europe's top adventure tour operators.