Typically if I have to travel with just one lens, I’d use 35mm. But if I travel with two lenses, I choose Elmar 24mm and Lux 50mm. Elmar 24mm is for landscape shots, and Lux 50mm is for portrait shots.
Leica Elmar 24mm lens has almost no noticeable distortion, so I often use it for portrait shots with a landscape background.
Here are a few photos I took with Elmar 24mm in California.

Due to asph lens design, it’s super hard to make a flare (or ghost)effect. But when it does, it produces a really warm image.


This isn’t exactly a portrait shot but technically it’s a portrait shot of an animal. You wouldn’t be bothered by lens distortion which typically happens with a wide focal length lens.
I didn’t finish editing my travel photos yet, I will post some more as soon as I am done.
If you’re looking into a wide-angle lens for landscape photos, I’d like to recommend a 24mm Elmar lens. I am glad I brought this lens with me on this trip.