Patagotitan mayorum, discovered in 2017, was thought at that time to be a dinosaur that was 121 feet long and to have weighed in at 69 tons. More recent study has revised its length to 102 feet, with a corresponding decrease in weight. In any case, it was one big animal that you would probably not want to see on your morning hike. See:
https://en.wikipedia.org/wiki/Patagotitan