see if you can find it.

The chick at far right could use a good shave.

Someone once told me that mixed seating was assur from the shulchan aruch (no less) no matter where. I guess mixed standing was okay then.

Maybe Woman #2's hump functioned as a mechitza.

are they all Jewish?

I should think so.

Just by the way, for many years prior to the miraculous victory in 1967 CE it was prohibited by law to bring benches or to erect a mechitzah at the Western Wall - anything like that was seen as disrupting the status quo and a grab by the Jews to establish their domain.

Until fairly recently (within the past 10 years) there were no mechitzos in most holy places, including Kever Rochel and the Maaras Hamachpela and I believe even the Kever of the Rashbi.

I don't know of any authority that holds that mechitza is required except for public davening, not yechidim or people saying tehillim.... (maybe the Kosel today is different because it has the status of a permanent shul, but back then it certainly didn't).

what about for a shiur or a wedding feast or a curriculum night at beis yaakov?

A wedding is different because it is 1. A social event, and 2. there is a genuine risk of "licentiousness" and "frivolity".
But would anyone say that there MUST be a mechitza at the chuppah (or Lo aleinu a leviyah)??? Even in Mea Shearim they don't have that, the men and women just stand separately....

A shiur could go either way. On one hand it is "Holy" so it may not be "appropriate" for men and women to sit together, but it would be hard pressed to declare that the HALACHA. I have been to MANY mixed shiurim.

As for other events, again it depends. We are NOHEG to have separate seating, but I hardly think that is mikker hadin....

"Inappropriate" doesn't always translate to ASSUR. And all 3 examples are not yechidim, but a cohesive GROUP activity....

There's a teshuvah in Bnei Banim that you don't need a mecthitzah even for davening if it's a temporary situation, like you're on a tiyul and it's time to daven, or when a bunch of men break away during a wedding meal to daven maariv in a corner, if I recall correctly. Rather, to require a mechitzah meikkar hadin, you need both 1. zman tefillah in 2 a makom tefillah. If I recall correctly.
That means a shiur in a shul doesn't require a mechitzah, and neither does davening in a temporary place.

Which is why back then no mechitza was required at the Kotel, today I think it has the din of a regular shul...
It may have been a MAKOM tefila (even that is arguable how "kavuah" it was), but when a bunch of yechidim come to daven, or say tehillim that is not "zman tefilah" or "tefilah btzibur"....

Yeah, I know. I was supporting what you said.

There was an incident in the 1920s when a Chassidishe Rebbe visiting from Europe (his identity escapes me at the moment) tried to have a mechitza erected at the Kotel. The Arabs and the British threw a fit.