The Promenade Concert series started by Henry Wood in the 1890s.

Accessible "proper" music presented to the masses and has become a major institution in the UK.

They're a season of summer concerts, held annually and often broadcast on the BBC, particularly the Last Night. I think the Boston Pops does something similar in the US, IIRC.

These concerts are unusual in that you can 'Prom', i.e. listen standing up in an area with no seats - either immediately in front of the orchestra or way up in the Gallery at the top of the building. Tickets cost £5 - half the price of the cheapest seats. Some Prom tickets are sold in advance in the form of season tickets for half or all of the concerts, but most are sold on the day and you can just turn up and queue.

A 'promenade' concert is one where the audience can wander around, in and out and (in the 19th C at least), make assignations with their mistress or trollop while being at a perfectly respectable event.

In the 18th century a "promenade" social was an event where people would walk around e.g. Bath or Edinburgh showing off their best clothes, mingling socially without introduction or formalities, and make assignations with their mistress or trollop while being at a perfectly respectable event.

In Edwardian times, a 'promenade' was a paved area near the sea-side where the newly leisured lower and middle classes could stroll around taking the air, and meeting other people informally, and make assignations with their mistress or trollop while being at a perfectly respectable event.

Now what was that about american teenagers again?

No, because I was there, standing in the arena! It was very interesting to hear the incidental music with accompanying scenes from the series but no dialogue to get in the way. Very much looking forward to seeing the TV version.