Due to his profound knowledge of antique architecture, he took part of Ernst Curtius' archaeological expedition to Asia Minor.
He was part of the leading directory of the major excavations in Olympia (1874–81), and took part in the planning of the whole enterprise,[1] which was at first scheduled to last no more than five years. At one point, he was even leader of the excavations. He was also the editor, together with Ernst Curtius, of the publication of the excavations report.
Adler died in his home city of Berlin, aged 80.
Archaeological works (as co-editor, together with Ernst Curtius)
Adler designed and built many structures, among them 300 churches, some villas, castles and manor houses, holiday resorts, urban residential buildings etc.
Lutheran St. Peter's Church, Berlin, as master builder for Heinrich Strack as of 1850 (destroyed in WW II)
Lutheran Christ and Garrison Church, Wilhelmshaven, as architect between 1869 and 1872 (severely damaged in WW II, rebuilt)
Lutheran St. Peter's Church, Bromberg (today's Bydgoszcz), as architect between 1872 and 1878 (converted into Catholic Sts. Peter and Paul Church on 2 July 1945)
Lutheran Redeemer Church, Jerusalem, as architect, built after his designs by his pupil Paul Ferdinand Groth between 1893 and 1898
Lutheran St. Peter's Cathedral, Schleswig, as architect he designed and added a new western main tower between 1888 and 1894
Catholic St. Peter's Collegiate Church, Bad Wimpfen, as architect he renovated the church and designed and completed the unaccomplished towers between 1898 and 1902.