Prague is full of esoteric and exotic features, which makes a random walk around the city a magnificent way of spotting all that the City of a Hundred Spires has to offer. If you’re in Prague on the summer solstice, you can watch a rare double-sunset on the same day if you’re around the Charles Bridge.

Charles bridge

The Charles bridge is Prague’s iconic site.

I’ve written about the significance of some of the statues on the bridge, as well as the superstition that led to its design and construction.

It’s clear that King Charles IV was an avid astrologer and alchemist. He chose everything about the bridge with great care and attention¹.

King Charles was also responsible for construction and renovations of the castle. The same architect also worked on both projects¹, so a connection between the two isn’t surprising.

The view of the castle from the bridge is familiar to tourists, who will stop for that scenic shot of themselves with the castle as a backdrop. Tourist guides garble the statistics as they walk by – largest castle complex in Europe, built 1000 years’ ago – but few mention the solstice.

So what is this connection with the summer solstice and the setting sun?

Prague castle sunsets

The view of the castle will vary depending on where you are on the bridge. At 9.5 metres in length (almost 31 feet), this isn’t surprising. The best location to see the sunset is from the base of the Old Town Bridge Tower. The approach to this tower is where a soon-to-be-crowned King would first glimpse the castle when on the Royal Coronation route. This makes the right-bank, and the Old Town Tower, important.

The sun’s ecliptic path means that the sun will usually set to the left of the castle most of the year, i.e., closer to Petřín Hill. On the summer solstice, the sun sets behind the castle itself. Watching the silhouette of the castle as twilight paints the sky is magical in its own right. The castle is on a hill so the sun will dip behind it around 40-60 minutes before it goes dark, allowing you to enjoy the bridge and the view for a little longer.

What’s the trick behind a double-sunset then?

Double sunset

One major part of the skyline is the Cathedral of St Vitus. The architect designed it in such a way that the sun’s path dips behind the main building, only to re-emerge above the apse before setting a second time. This only happens on the summer solstice (to be precise, it happens 3 days on either side of the solstice but for greatest effect, be there on the day).

This means that as the sun sets, the cathedral is first obscured by the sun’s glare. There is a proper sunset because the sun is now behind the cathedral itself and no longer visible. It’s worth noting that the sun sets right above the location of the tomb of King Wenceslas¹. Within minutes, the sun appears above the apse at the rear end of the cathedral.

There’s a lost rotunda connected to King Wenceslas across the bridge in Mala Strana.

The sun illuminates the sky and sets for the second time before disappearing for the day.

Some wonder if this is a huge coincidence, or if it is part of King Charles’ plan. There’s no documentation that shows any intent for this effect, so we will never know. It’s too much of a coincidence to be random, if you ask me.

The effect is magical, especially if the weather is in your favour. Make sure to get there in good time. On the solstice, the base of the tower is full of photographers and solstice watchers waiting for the double sunset.

References

1. Prague’s summer solstice alignment; Raymond Johnston; Magic Bohemia; (Retrieved 2022-09-01) [↩][↩][↩]

Remember: links were correct at time of publication.