Comment by dredmorbius

For those near the SF Bay Area, the De Young Museum in Golden Gate Park, with its copper-cladded exterior, is an excellent instance of this.

I suspect that the effect was unintentional, but (at least until internal WiFi access was provided) the consequences were delightful.

Any metallic grid should attenuate signals effectively. Old-school lathe-and-plaster construction (which often incorporates a wire mesh) is well-known WiFi / cellular poison:

<https://www.techwalla.com/articles/how-to-get-a-wifi-signal-...>