Trafalgar Square 21045

Time for another lighting project!

We were very lucky to buy the LEGO Architecture set - 21045 - in London's Leicester Square store, just around the corner from the real Trafalgar Square.  And we got to meet the designer - Rok Kobe too!

Well that was 2019 and we've been a bit busy since - and as there's no sign of an official Light My Bricks lighting kit for this we've had a go ourselves.

Here's what the model looks like when built.

Image (c) The LEGO Group

Lighting Options

This set has lots of places we can light up of course.

  • The National Gallery.  Dominating the back of the model this huge building is filled with windows made with a fab SNOT technique.  It also has glass skylights on top.
  • The building interior.  Accessed from the rear are three small gallery rooms.
  • The Fountains.  Two huge fountains with lots of trans-light-blue pieces are perfect for lights.
  • The Street Lamps.  A total of 8 street lamps wrap around the front of the square.
  • Nelson's Column.  This is lit up in real life of course, with flood lights from below and lights at Nelson's feet illuminating the statue.
  • The vehicles.  There's two buses and two taxis here too.

We experimented and decided to leave out the building interior, the column, and the vehicles.  Everything else gets lit up!


To fit our lights we'll have to lift a lot of tiles and take the roof off the National Gallery.  There's something you don't often say.

So first off - remove Nelson's Column and all the trees.  They'll only break off otherwise.

And pull the dome off the top of the building too.  Now we can get cracking!

The National Gallery

We'll start here as it's a pretty straightforward part of the project.

We're going to assume that the wiring can be hit behind the building, so won't need to worry too much about cable routing.

To light up the main windows we're using 4 x Warm White Strip Lights with 3 x 5cm Connecting Cables and 1 x 15cm Connecting cable.

First pull the whole roof - this is surprisingly easy if you grip the front and back on both sides near the end skylights and wobble it gently whilst lifting.

Daisy Chain the lights together as follows:

15cm Cable > Strip Light > 5cm Cable > Strip Light > 5cm Cable > Strip Light > 5cm Cable > Strip Light.

Then insert the end strip light into place on the right of the building (viewed from behind)

Lay the next two strip lights across the middle section - you can remove that white 2x3 plate for ease.

And the final light obviously continues in the left section.  Try and run the 5cm cables as neatly as possible, and enusre you aim the strip lights so they face the front.  Note that I haven't stuck these in place - these were old lights from previous experiments so weren't very sticky anyway!

Run that 15cm cable directly out the back at this point through the removable wall section.

Next up we'll fit a cool white strip light into that front portico section.  This is dead easy - it fits perfectly and sticks using the build in adhesive backing.  Connect a 15cm Connecting Cable before you stick it into place.

Finally replace the gallery's roof back into place with the two cables coming out together in that left hand removable wall section.

The Fountains

Both fountains are set up exactly the same - we'll just show the one here.

First pull off the top fountain section and carefully pull out the back of the 1xx Trans Light Blue bricks.

Take a 30cm Cool White LARGE Bit Light and place it in the empty spot between the studs and replace the 1x2 Trans Light Blue brick over it.  Be careful here to route the cable to the left and keep the LED facing straight up and as central as possible.  It may take multiple attempts but this will be worth it!

Replace the fountain pieces and connect up that LED to see if the light works okay and looks good.

Now we just have to hide the wires!

First lift and pop out the sloped road section.

Then carefully pull out the wall section with the tiles on top.  If any parts fall off just pop them back on to make replacing this easier!

Then you'll be able to lift out the section which has the jumper plates on top.

Now we just need to remove a few tiles to reach the fountain.  A brick separator is really useful here, particularly since the first tile is a 2x4 which is partly trapped under that clever staircase system.

Slip out that 2x4 and the white 1x6 next to it and we're good to go.

Run the Bit Light wire out across the exposed section, keeping it between the studs.  It really doesn't matter which route it takes, but straight down the middle works best.

Replace the 1x6 White Tile and the fountain section and push gently into place to cover the wire.

Then repeat with the 2x4 LBG tile.

Pop back the two sections of wall and it should look like this:

Run that wire down through the hole and under the set, reaching back to the corner where the other wires are.  Don't replace the sloped road section - we'll need that left open for the next stage.

Now that's done - do it all again on the other side!

The Street Lamps

Again we'll show just one half, and the other half is up to you.

We start with removal of a load of tiles to allow us to hide the wires.

Then take a Micro 4-port expansion board and carefully insert all four 15cm Micro Bit lights into it.  On the end connector fit a 30cm Connecting Cable.

The wire length here is only -just- enough, so positioning is vital.

Start with the Micro Bit Light furthest AWAY from the connecting cable.  Insert it into a lamp post between the black telescope and the trans-clear stud.  There's no perfect way to hide the wire, but it's pretty subtle if you keep it vertical down the back of the lamp post.  

Place the lamp post in the spot closest Nelson's Column and replace the 1x1 LBG tile to secure the wire.

Repeat with the next two lights, replacing the tiles as you go.  Keep the wires separate so you don't have more than two wires between any two studs. 

Once the tiles are back in place, use tweezers to gently encourage the wires to hide behind the lamp posts.

The smaller lamp is built in a similar way, with the Micro Bit Light underneath the trans-clear stud.

Set this in place and push the wire down before re-fitting the 2x1 jumper plate on top of it.

Et Voila - the wires should be almost invisible.

Replace the final tiles, ensuring that no wires are caught on top of a stud.  This will damage the wires and make pushing the tiles flat impossible.  As ever I recommend tweezers to push and tweak the wires into place whilst lowering the tile down.

Replace also the sloped road section and flip the model up on its side to secure the wires.

I used tweezers (again) to pull the wires out and then wrapped them into bundles to keep them neat.

Finally use a piece of sticky tape to hold the micro expansion board into place.  It should be ports-up and as close to the back as possible, to allow the sloped road to fit properly.  This is optional but makes it easier to move and position the set.

Now put the model back down, flip it around, and do the street lights for the other side!

Connecting it all up

That's it for lights, now we just need to connect all the wires together with an 8 port expansion board.  If you're careful you can then push this snugly into the room at the back of the National Gallery, though really you'll never see it anyway.

2 Ports for the Fountains
2 Ports for the Street Lamps
2 Ports for the National Gallery lights
1 Port for a USB cable or battery pack

Set the model down and give it a final gentle squeeze to push the tiles down into place.

And now at last you can replace all the missing Lego parts - the trees, cars and so on, and enjoy it.

Parts Used

This project used the following components:

  • 4 x Warm White Strip Lights
  • 1 x Cool White strip Light
  • 3 x 5cm Connecting Cables
  • 2 x 15cm Connecting Cables
  • 2 x LARGE Cool White Bit Lights
  • 8 x White 15cm Micro Bit Lights
  • 2 x 4-port Micro Expansion Boards
  • 2 x 30cm Connecting Cables
  • 1 x 8 Port expansion board

The pieces used can be bought as a custom bundle for £68 with free UK shipping.  Message us if you'd like this and we'll set it up as a custom quote for you.

Any questions?

Feel free to message us any time, or post a public comment using the form below!

Happy building



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