The first-ever opportunity to walk under the river Shannon will be available this weekend in Ireland.

The Shannon is the largest river in either Britain or Ireland and the new tunnel was built at a cost of $1 billion.

A  chance to be one of the first people to walk under the river Shannon is being offered to people in Limerick and Clare.

The 1,000-yard tunnel and linked 15-mile highway will connect major motorways and act as a bypass for Limerick City. It is the most expensive motorway stretch ever built in Ireland.

The tunnel will open later this summer, but pedestrians will not be allowed walk through this weekend.

From 10 a.m. to 7 p.m., at the weekend visitors are being allowed to walk under the river Shannon for the first time in history. The precast tunnel was previously on display before it was placed into position in July 2008.

The new tunnel and highway links the N7 Dublin Road, the N20 Cork Road and the N18 Ennis Road.

When the tunnel opens officially later this summer, a toll of $3 is to be charged for private cars.

The tunnel operator is Direct Route Limerick Ltd, which holds the concession for 35 years.