The Mysterious Haganah Mission Building Plaque on East 60th Street

In front of the Harmonie Club on East 60th Street between Fifth and Madison Avenues in New York City you will find in the sidewalk underfoot the above plaque that proclaims it as the location for the, "Clandestine Mission of the 'Haganah', Israel's pre-state defense forces, which labored unceasingly for Israel's independence and survival," between 1945 and 1948.

Wikipedia tells us about the club as a meeting place for Jews but not specifically for the Haganah,

The membership was originally entirely Jewish, and it served as the location of the meetings of the American Jewish Committee for several years, especially in the tumultuous 1930s; it took a leading role in resettling refugees from the Nazis and in ensuring their contribution to the Allied war effort. Albert Einstein and other prominent Anti- Nazi figures of the day sponsored events at the club to raise awareness of the persecution of Jews by the Nazis.