The Victoria and Albert Museum in London has a special exhibition of Cartier jewelry, watches and clocks set to open on April 12, 2025. It runs until November 16, based on the booking calendar. The exhibition costs £27 on weekdays and £29 on weekends--pricey, but the museum's permanent gem and jewelry displays are excellent, and this is probably the world's best decorative arts museum. General entry to the V&A is free/donation-requested. The museum has to do something to help cover its costs.
All dates from opening through April 28 are already sold out, as are the first three weekends in May. There are individual time blocks sold out on many other days and additional time blocks with only 1 or 2 tickets remaining. This looks like it's going to be a hot ticket. It appears weekday attendance would give the best (but not guaranteed) chance of somewhat less crowded conditions. The best conditions in the regular jewelry exhibition are at opening time.