In Amsterdam we have a long standing interest in the properties of weakly interacting quantum gases at low temperature. The first quantum gas that could be studied experimentally, spin-polarized atomic hydrogen, was stabilized in Amsterdam in November 1979 by Silvera and Walraven . This breakthrough was realized within the domain of low-temperature and condensed matter physics by introducing a liquid helium coated sample cell to contain the gas. Hydrogen being a unique example, the interest in weakly interacting gases at ultralow temperatures remained restricted to mostly theoreticians and a handfull of experimental groups. A wealth of properties was investigated but the presence of surfaces restricted the experimental investigations to the temperature range 0.1-1K.