Mahabharata 3.91.4

श्वापदैरुपसृष्टानि दुर्गाणि विषमाणि चअगम्यानि नरैरल्पैस्तीर्थानि मनुजेश्वर

śvāpadairupasṛṣṭāni durgāṇi viṣamāṇi caagamyāni narairalpaistīrthāni manujeśvara

Our plain-language meaning of this verse is waiting for scholar review.