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https://getoutside39507958bf.blob.core.windows.net/blobgetoutside39507958bf/discover/wp-content/uploads/2024/03/trig-point-pillar-project-hero2.2459c66550e35ba20830f8037c980982.jpg1920485The trig pillar was first used in the retriangulation of Great Britain on 18 April 1936. With over 6500 built, they were vital in map making. Here's everything you need to know about trig pillars including 10 great trig point walks.