The interaction between adjacent bubbles plays an important role in boiling heat transfer on a micro heat source. In this paper, the visualizing bubble behaviors during subcooled pool boiling on microwires were revisited experimentally. Bubble circling phenomena, the circling of small bubble around a larger one for subcooled boiling on platinum microwires submerged in ultrapure water or self-rewetting fluid, were investigated. Different types of bubble circling phenomena, including small bubble sweeping, departing, rotating, returning or chasing at a larger bubble interface, were described in detail. The roles of Marangoni effect and viscous force were analyzed in the process of bubble circling to understand the mechanism of bubble behaviors on micro heated surface. The investigation on the bubble circling phenomenon can help verify the crucial factors that influence the bubble dynamics, bubble interaction and boiling heat transfer. The bubble dynamics in this phenomenon also makes it an interesting choice for many microscale applications. (C) 2013 Elsevier Ltd. All rights reserved.