Old staircase in hallway to bunker?

My house is about 230 years old - I lifted some tiles up in my hallway and discovered a wooden hatch - upon lifting the hatch there is a stairway leading down into a large cobweb filled room that smells rather stale. There are newspapers from the 1920s and large boxes/crates in the corner. In another corner, there are "ammunition" boxes circa 1930 - there are old gas masks -There is also another metal grid thing that appears to be another staircase down but I can't open it as I'll need large metal grinder industrial cutters. Should I open the crates up or tell authorities? What the hell is this place??