In even space-time dimensions the multi-loop Feynman integrals are integrals
    of rational function in projective space. By using an algorithm that extends
    the Griffiths–Dwork reduction for the case of projective hypersurfaces with
    singularities, we derive Fuchsian linear differential equations, the
    Picard–Fuchs equations, with respect to kinematic parameters for a large class
    of massive multi-loop Feynman integrals. With this approach we obtain the
    differential operator for Feynman integrals to high multiplicities and high
    loop orders. Using recent factorisation algorithms we give the minimal order
    differential operator in most of the cases studied in this paper. Amongst our
    results are that the order of Picard–Fuchs operator for the generic massive
    two-point $n-1$-loop sunset integral in two-dimensions is
    $2^{n}-\binom{n+1}{\left\lfloor \frac{n+1}{2}\right\rfloor }$ supporting the
    conjecture that the sunset Feynman integrals are relative periods of
    Calabi–Yau of dimensions $n-2$. We have checked this explicitly till six
    loops. As well, we obtain a particular Picard–Fuchs operator of order 11 for
    the massive five-point tardigrade non-planar two-loop integral in four
    dimensions for generic mass and kinematic configurations, suggesting that it
    arises from $K3$ surface with Picard number 11. We determine as well
    Picard–Fuchs operators of two-loop graphs with various multiplicities in four
    dimensions, finding Fuchsian differential operators with either Liouvillian or
    elliptic solutions.

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