What was the most significant moment in the history of Barney and Robin's relationship on How I Met Your Mother?

Barney and Robin's relationship on How I Met Your Mother was an important part of the show's storyline. While they had their ups and downs, there was one moment that stood out as the most significant in their relationship history.

The most significant moment in the history of Barney and Robin's relationship was when they got engaged in Season 8, Episode 12 "The Final Page Part Two". After a long and complicated journey, Barney finally realized that he was in love with Robin and wanted to spend the rest of his life with her.

The proposal was grand and romantic, taking place at the top of the World Wide News building in New York City. Barney had planned every detail, including a video of all the moments they shared together, and a Robin Sparkles song playing in the background. Robin was completely surprised and overwhelmed, and she said yes to Barney's proposal.

While their engagement was short-lived and they ultimately didn't end up together, the proposal itself was a standout moment for their relationship. It showed that even though they had been through a lot, including a failed relationship and a broken engagement, they still had strong feelings for each other and were willing to take that leap of faith.