How many calories does a 20 km walk burn?

Ugh, 20km is a LONG walk! I mean, seriously, that's like...a half marathon, right? Okay, so if I were doing it (and I'm around 60kg, give or take – who's really counting?!), I'd be picturing at least four hours of solid walking. Four hours! What playlist would I even choose? Anyway, calorie-wise… I've seen those calorie calculators online, and they tend to say something around 100-120 calories burned per kilometer walked. So, for 20km… Hold on, let me do the math… That's like, what, 2000-2400 calories?! That seems like a LOT. Maybe I’m overestimating. My friend Sarah, she's a bit of a fitness guru, told me about this time she walked something crazy like 15km and burned around 900. So maybe for me, 20km would be more like, I don't know, 1200-1500? It definitely depends on the terrain too. Like, remember that hike we did in the mountains? Killer views, but SO many uphill climbs. I bet I burned way more calories then than just walking on flat ground. Plus, I was practically running down some of those hills! So yeah, I’d guess somewhere between 1200 and 1500 calories for a 20km walk. And honestly, the calorie burn is great and all, but the real reward? That post-walk glow. Nothing beats it.