AAO Colloquium. Tuesday, 10th October - 3:30pm AAO Conference Room Bars in active and non-active galaxies Johan H. Knapen University of Hertfordshire and Isaac Newton Group Bars occur in most disk galaxies, and are believed to be responsible for gaseous inflow from the disk to the central regions. There, the gas can either flow into the centre and possibly cause nuclear starburst or AGN activity, or it can be slowed down by dynamical resonances in which case circumnuclear ring or spiral structure can occur. I will discuss this phenomelogy using high-resolution observations, and will explore the exact relationships between the bars in the host galaxies and the (circum)nuclear activity.