Today we were at Husbygropen in Ekerö, also known as The Blue Lagoon - about an hour drive from Stockholm center. My expectations were wrong as I was hoping for an oasis in the middle of nowhere. Instead we found a PACKED beach with people walking around the whole lake in circles trying to find a spot to lay their towels. The get-away, although short, was worth it as this place is known for the "abroad-feeling" it gives. The water is turquoise blue and clean, and the bottom is of sand, unlike most beaches in Stockholm where there is twigs and stones underneath. It gets very deep only a few step in, so those like myself, who aren't great at swimming, should bear that in mind. Other things that you should know if you are to visit the place, is that there is no store in sight, so make sure to have enough food and drinks for the day. You can bring your grill like us. Another thing to be aware of is that there are some bugs all over the place, I think they are called flying ants - some repellent spray would have been good to have. You pay 40 SEK for parking on the way in, and it is up to you if you actually find a place to park - it can be hard on days like this when it is crammed. The place is reachable by public transport as well - a normal SL card would do. There is a bus stop called Vibohär ("We Live Here") at a 20 min walk from the beach! :) Here is a good blog post about Den Blå Lagunen in Swedish.
