Olivine city is a port city very similar to the port cities of Vermillion of Kanto, Slateport of Hoenn, and Canalave of Sinnoh. Olivine's most distinguished structure is the lighthouse which is powered by the electricity of an Ampharos. The Gym Leader of Olivine is a master of Steel type pokemon so they have a really strudy defense, something that must take a lot of burning will to get around. Good luck.