29686980744_d9098712c8_kA rendering of the Stad Ship Tunnel in Norway.Norwegian Coastal Administration
Stretching over 15 miles, Norway's Lærdal Tunnel has been the longest road tunnel in the world since it was built in the 1990s. 
Now, the country will construct the world's first tunnel for ships — which will get between 70 and 120 vessels per day.
As noted by BBC News, the tunnel started gaining public support in the 1980s, and the Norwegian Coastal Administration (NCA) has since embarked on several feasibility studies to see how it could come to fruition.
In March, Terje Andreassen, the tunnel's project manager, told Business Insider that the NCA submitted its findings to Norway's Department of Transport. The project got official approval in April. It will be financed by the Norwegian Parliament, which has already designated approximately $117 million ($1 billion NOK) for the NCA's research.
Construction will likely start in 2019, and the tunnel is expected to open in 2023, Andreassen told the AP.
The NCA worked with Snøhetta, an Oslo-based architecture firm, to create renderings of what the tunnel will look like. Check them out below.