Underfloor storage compartments

Looking for suggestions on construction techniques for storage under the floor with access from the interior.
Pros\cons ?
How deep can the storage compartment be ?
How should the cargo area be constructed ?
Any links to previous builds and especially photos would greatly be appreciated.
TIA.
Pros\cons ?
How deep can the storage compartment be ?
How should the cargo area be constructed ?
Any links to previous builds and especially photos would greatly be appreciated.
TIA.