With this seed, you will start the game next to a desert village with a big Nether portal. You will find it at coordinates 85 ~ 25. Not far from the village, at 115 ~ -150, there is a shipwreck, and at coordinates 10 ~ 215, you can loot a desert pyramid.
How to use Big Nether Portal on Spawn seed
Start the Singleplayer mode
Select ‘Create New World’
Then click on ‘More World Options…’
In the ‘Seed for the World generation’ field, enter -6853991819613597643