An abandoned church at the bottom of the sea

In my opinion, it would be interesting to have a church hidden in the depths of the sea, far from dry land, and it would be cool if there were an abandoned cemetery nearby; that way, the player would have two areas to explore.

Structure Descriptions:

1. The church would be similar to the Mont-Saint-Michel Abbey church

2. The church and the cemetery would be large in size to make it harder for the player to find the chests

3. There would be many Drowned in the church, and especially in the cemetery, to hinder the player's exploration

4. In the cemetery, the chests would be hidden inside the graves, and the player would have to dig them up to find the chests—though not every grave would contain one.

5. Inside the church, there will be many rooms, corridors, secret passages, labyrinths, and traps.

6. Since the church and the cemetery will be very dangerous, the chests will have a high chance of containing valuable items essential for the player's progression in the world, rewarding their effort.