A Christmas tree which is 110ft high (35m) has been decorated at Kew's West Sussex garden.
The tree when lit up can be seen on flights approaching Gatwick
When lit up, the giant redwood will be visible on board flights approaching Gatwick Airport.
Two electricians spent a day replacing all 1,800 light bulbs before a pair of cranes were brought in to put the lights on the tree at Ardingly.
Ten people were needed to decorate the tree, outside the Elizabethan mansion at Wakehurst Place.
Conservation manager Ian Parkinson told BBC South East Today there was "no secret" to avoiding tangles.
He said: "We just put them in the box at the end of the season, and the next year, when they are in a tangled mess, we unravel them laboriously."
Two cranes and two electricians were needed for the work
Another team member said there was no secret to rigging the lights in straight lines.
He said: "The best thing to do, when you get down on the ground, is just to turn away and walk away and think 'job done for another year'."
Wakehurst Place spokesman Trevor Butler said making sure the bulbs worked required "a belt and braces approach".
He said: "We have two electricians who spend the best part of a day with the lights strung out across the Chapel Lawn here in front of the mansion.
"They replace all 1,800 bulbs - they are all new every year - and they spray each one with silicone grease to repel any moisture in case it rains."