During the June 1998 MEDOC campaign, a polar crown filament was followed during 4 days from June 18 until its eruption on June 21.
The paper presents the fine structure and dynamics from observations in H-alpha, using the Swedish Vacuum Solar Tower (SVST) telescope at La Palma, and in the coronal Fe IX/X 171 Å line with TRACE. The filament was in addition observed over a wide range of temperatures with the spectrographs aboard SOHO, - CDS and SUMER. These observations allow us to derive the velocity field of the filament and its environment. Preliminary results are presented.