While Jasmine has no fightable junior Trainers in her Gym, the Lighthouse poses a challenge which provides more than enough of a counterbalance to it, as there are many Trainers on each of its floors. In Generation IV, Gentleman Preston and Lass Connie are actually Trainers from the Gym, and will return there once Amphy has been cured.
Also in Generation IV, once the player has spoken to her, Jasmine opens a door for them leading to an elevator that goes from the top floor directly back to the bottom.
The Shining Lighthouse, as it was called in the English dub, appeared in Fight for the Light!. It remains an important landmark and a popular tourist attraction in Olivine City, however a neighboring electric lighthouse now does most of work. An Ampharos has historically been the light source, and this tradition continues under Myron's watch.
During Fight for the Light!, the group ventured over to the Shining Lighthouse so Ash could challenge Jasmine to a Gymbattle. However, Jasmine was too concerned about her Ampharos nicknamedSparkle because it was ill. Team Rocket showed up on the scene and in their scheme to capture Sparkle they also put a hole through the Shining Lighthouse's roof. Luckily, Janina and her Onix were able to rescue Sparkle, and she later agreed to venture to the Cianwood City pharmacy to retrieve medicine to treat Sparkle. Janina obtained the medicine in the following episode, and returned to Olivine City while Ash's group decided they would travel through the Whirl Islands first.
In Throwing in the Noctowl!, the light of the Shining Lighthouse helped Wings Alexander through the thick fog and avoid crashing his plane, which had Ash's group and Team Rocket aboard, into the Olivine sea cliffs. Janina, Jasmine and a fully recovered Sparkle waved from the Shining Lighthouse as the plane corrected its course.