This guide is suitable for current RuneScape and Old School.
Enter the Lumbridge Swamps and search for a group of Adventurers.
Talk to the Warrior and he will let slip that they are searching for the lost city Zanaris, but will then refuse to tell you anymore. Head to the trees near the camp and you will find one tree with just the option to 'Chop tree' rather than 'Chop down tree.'
Click on that tree and a leprechaun called Shamus will appear out of the tree. Talk to him about Zanaris and he will tell you about a special tree found in a cave at Entrana, called the Dramen tree.
Make sure you have no armour or weapons on you, apart from runes. Head to Port Sarim and talk to one of the Monks on the dock and after searching you, they will take you to Entrana. Upon arrival, head north-east over the bridge, and then west to the dungeon.
Climb down the ladder, and start killing Zombies near the entrance until they drop a hatchet.
Now follow the path down and turn right at the Greator Demons and you will see the tree. Attempt to cut it, and a level 90 Tree Spirit will appear.
Fighting the Spirit
Near the Dramen tree will be some mushrooms, head behind them and you will now be able to kill the Tree Spirit using magic in your safespot.
Once the Tree Spirit has been defeated, use your hatchet to cut a branch of the Dramen tree and use the knife to carve it into a staff.
Note: It may be a good idea to cut several branches off and make them into staffs, in case you need spare.
Getting to Zanaris
Use the Lumbridge home teleport to get out of there, and then head back into the swamp. Search for an empty shed which is near the Water Altar.
Equip your staff and enter through the shed to arrive in the Lost City of Zanaris.
Congratulations! Quest Complete!
Guide Made by: Deathslayer
Corrections submitted by: Doctor Shemp, DaDa, Yolk, Ashwin, Dx1438, Majinvegito3, Power of Five