This week I finally decided to invest in the Lee Filters its holder and a remote control.
I took the Big Stopper (10 Stops) to improve my landscape and sea side pictures, to create this blur/fog effect. 
As I'm going to Valencia next tuesday, I can't wait to test it on the sea shore :-)
Here is the first picture I took this afternoon in bright sunlight, in Zurich.

Nikon D4, Nikkor 24-70 2.8.
60.0 s. f/22 - ISO 50

click to enlarge