You can just go into Disney Hall
The Walt Disney Concert Hall, where the LA Philharmonic plays, is a pretty crazy looking building! It was designed by Frank Gehry and it looks like a bunch of fucked up aluminum boxes. I like it a lot. I also like its air conditioning.
Here is a secret: you can go into Disney Hall and just walk around! You can go in there and use its bathrooms!!
I recently took my family in here to walk them around, show them the weird architecture, and use the bathrooms. Warning: I do not actually know when Disney Hall is open to wandering members of the public! I have friends who have taken their engagement photos here, and they just wandered in on a weekend with their photographer to do that. I've also wandered in on weekends as well. I've never tried wandering in on a weekday. Every weekend I've tried to get in here, I've been let in.
Like the outside of the building, the inside is full of non-rectilinear spaces. It's very creepy and cool and empty, and extremely heavily air conditioned. We came in with a group of nine people, including several chatty kids, and nobody minded us hanging out on the first floor.


We then took a spiral staircase near the front entrance up to a strange aerial walkway that encircles the entire upper part of the auditorium. This is also open to the public. You can see it on Google Maps:

In this screenshot, I've traced a route which starts with strange, unsettling architecture and ends with a surprise visit to a secret garden (the blue arrow). If you are taking guests along this route, you may want to just do the garden, which is also totally public. You can access it by scaling the large flight of steps at the corner of S Grand Ave and W 2nd Street. But if you go northeast along Grand Ave and go up the spiral staircase near the front entrance, you get a route with a bit of surprise to it, which I like. Follow the red arrow to do what I did.

The climb can be pretty intense. You are gonna get some weird views of some weird metallic structures. Turn right at the first intersection and keep climbing crazy staircases; you'll wrap around the building counter-clockwise.
At the first major landing, you get some really crazy views of the other Gehry building across the street - a luxury apartment building called The Grand:

It looks like a bunch of stacked boxes, and is also full of weird non-rectilinear angles. You can probably actually see the misalignments better from the street:

The path I drew with the red arrow takes you around behind some of the large metal panels on the facade of Disney Concert Hall. You will get to see how they're attached to the building and look at some of the (locked off) pathways that maintenance probably uses to check on them. It's very cool. I completely forgot to take pictures! They were simply too cool for me.
You'll then descend a long staircase and find yourself at the end of the red arrow, in a rooftop garden which is completely delightful, very shady, and contains a very unusual flower-shaped fountain sculpture. When I last visited, there were actually a ton of people strolling around up here, or relaxing in the shade. It's lovely! The garden even has its own page on the Metrolink website, for some reason.
I have no pictures to share, however, because all the pictures I took have my young relatives in them, and I'm not gonna put them on the internet. So you can just look at that Metrolink site, or at this page on the DTLA tourism website. Both pages focus on the fountain sculpture, which is very striking.
Once you finish with the garden, you can exit down the staircase at the corner of 2nd and Grand.
This is one of those "secret gems of DTLA" which you find on every tourism website but which nobody actually visits in real life. I am telling you: go there! Go there if you're gonna visit The Broad museum next door. It's right across the street and it's very calm and cool and nice. You can take some great pictures. I mentioned my friends had their engagement photos done here - they're really excellent pictures.
Downtown LA has had a terrible reputation off and on since I moved to LA, but I still think that it is a sign of poor character to be afraid of it. Loads of people live here. It's a totally normal place. You can become a person of Culture and Wisdom by coming here and visiting its many delightful venues, museums, restaurants, and gardens. This is one I strongly recommend - and it has great AC and bathrooms!!