Who knew this was ILLW, or International Lighthouse Lightship Weekend?
Well, in Greece the Navy has opened 30 Lighthouses to the public, who can visit and find out about their history and the way they work.

Lighthouses are used to mark dangerous coastlines, hazardous shoals, reefs, and safe entries to harbors. They can also assist in aerial navigation. However, the number of operational lighthouses has declined due to the expense of maintenance and use of electronic navigational systems.
Older lighthouses, especially half-ruined ones, are romantic structures, having about them the whiff of history – stories connected to lonely lives, pirates and derring do at sea.
Before the development of clearly defined ports, mariners were guided by fires built on hilltops. To improve visibility, the fires were placed on a platform, a practice that led to the development of the lighthouse.
The most famous lighthouse structure from antiquity was the Pharos of Alexandria, built by the Ptolemaic Kingdom between 280 and 247 BC. One of the Seven Wonders of the Ancient World, it was between 120 and 137 m tall, and one of the tallest man-made structures in the world for many centuries, until badly damaged by three earthquakes between AD 956 and 1323.

So if there is a lighthouse near you, perhaps today would be a good time to visit.