Staircase to the Moon is a natural phenomenon which occurs when a full moon rises over the exposed tidal flats of Roebuck Bay.

The Staircase to the Moon happens 2 - 3 days a month between March and October. The first two days of Staircase to the Moon generally also play host to the Staircase to the Moon markets at Town Beach. Here you can sample local produce, buy hand made products, a variety of international food, and enjoy the sounds of local entertainers. Another popular spot to view the event is The Mangrove Hotel Resort, with live entertainment every Staircase night.

http://www.visitbroome.com.au/discover/facts-figures/staircase-to-the-moon

Note: the markets are held on Monday 23 and Tuesday 24 May, not on the first night (22nd).