Piyang Kong Halmani

Seonjeongneung Royal Tombs

It sells monthly and lunchtime passes, which tells you what it mostly is: a working park that office workers and neighbours walk through, which happens to contain two royal tombs. Under-25s get in free, so for most young travellers the ticket price is irrelevant.

Starfield Library

It is a mall atrium, not a library in the quiet sense — there is no lending, and the photographs everyone comes for are of a space full of people. Power sockets and worktables make it a genuinely usable stop between COEX appointments.

SEA LIFE COEX Aquarium

Nobody should pay the gate price. The operator's own site sells the same adult ticket at a standing discount and drops it further on selected dates, so the number to plan around is the online one, booked before you arrive.

Bongeunsa Temple

The temple publishes no opening hours and no admission fee anywhere on its own site. What it does publish hours for is the bakery, the noodle canteen, the Buddhist-goods shop and the florist — which is a fair description of how the grounds are actually used.