Celebrating 20 Years Of Scientific And Technical Results With The Inaf-Tng Telescope

June 9th, 2018 marks the 20th anniversary of the first light of the INAF-Telescopio Nazionale Galileo. This paper is a resume of the main scientific and technical results obtained with the TNG, together with the history of the telescope, the instruments and the people who allowed for several successes and many lessons learned. We will point out what made the TNG a telescope which still can make competitive research in the large and extremely large size telescopes era.