According to the Dictionary of the Slovenian Standard Language (SSKJ) a likof, especially in a rural setting, is a feast after finishing the major construction work on a building.
As evident from the video below, however, a likof, with several maypoles, bands and a national flag flying from its top, was also celebrated on the conclusion of the structural part of the construction of the Ljubljana Skyscraper (Nebotičnik), at the time one of the tallest buildings in Europe and a symbol of Ljubljana's urban modernity.
Related: Old Photos of Nebotičnik