this narrow crack is the upper entrance
{"Image Make": "NIKON CORPORATION", "Image Model": "NIKON D7100", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop Lightroom 4.4 (Macintosh)", "Image DateTime": "2014:03:03 09:37:06", "Image ExifOffset": "218", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "794", "Thumbnail JPEGInterchangeFormatLength": "13850", "EXIF FNumber": "9", "EXIF ExposureProgram": "Aperture Priority", "EXIF ExifVersion": "", "EXIF DateTimeOriginal": "2014:02:25 11:27:06", "EXIF ApertureValue": "126797/20000", "EXIF MaxApertureValue": "43/10", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "22", "EXIF SubSecTimeOriginal": "3", "EXIF FocalPlaneXResolution": "47079/184", "EXIF FocalPlaneYResolution": "47079/184", "EXIF FocalPlaneResolutionUnit": "4", "EXIF SensingMethod": "One-chip color area", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "22", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0", "EXIF BodySerialNumber": "2511114", "EXIF LensSpecification": "[10, 24, 7/2, 9/2]", "EXIF LensModel": "10.0-24.0 mm f/3.5-4.5"}