  We present a new catalogue of 5,106 infrared bubbles created through visual
classification via the online citizen science website 'The Milky Way Project'.
Bubbles in the new catalogue have been independently measured by at least 5
individuals, producing consensus parameters for their position, radius,
thickness, eccentricity and position angle. Citizen scientists - volunteers
recruited online and taking part in this research - have independently
rediscovered the locations of at least 86% of three widely-used catalogues of
bubbles and H ii regions whilst finding an order of magnitude more objects. 29%
of the Milky Way Project catalogue bubbles lie on the rim of a larger bubble,
or have smaller bubbles located within them, opening up the possibility of
better statistical studies of triggered star formation. Also outlined is the
creation of a 'heat map' of star-formation activity in the Galactic plane. This
online resource provides a crowd-sourced map of bubbles and arcs in the Milky
Way, and will enable better statistical analysis of Galactic star-formation
sites.
