 Complete the following phrase:  On 24 August 1921, R.38 designated ZR-2 by the USN was destroyed by a structural failure while in flight over the city of Hull. It crashed into the Humber Estuary, killing 44 out of the 49 crew aboard. At the time of its first flight it was the worlds largest airship. Its destruction was the first of the great airship disasters, followed by the Italian-built US semi-rigid airship Roma in 1922 34 dead, the French Dixmude in 1923 52 dead, the British R101 in 1930 48 dead, the in 1933 73 dead, the USS Macon in 1935 2 dead, and the German 