A shelter (1, 2, 3) comprising: an outer longitudinal tubular structure (4, 104) having an outer wall (10, 110), a first-outer-longitudinal-tubular-structure end (30, 130), and a second-outer-longitudinal-tubular-structure end (40, 140) diametrically opposed to the first-outer-longitudinal-tubular-structure end (30, 130); an inner longitudinal tubular structure (5, 105) positioned within the first longitudinal tubular structure (4, 104) and having an inner wall (20, 120), a first-inner-longitudinal-tubular-structure end (35, 135), and a second-inner-longitudinal-tubular-structure end (45, 145) diametrically opposed to the first inner-longitudinal-tubular-structure end (35, 135); and a segmented annular portion positioned between the outer wall (10, 110) and the inner wall, said segmented annular portion comprising a plurality of segmented annular divider walls defining a plurality of through channels (50, 150) extending from the first-outer-longitudinal-tubular-structure end (30, 130) to the second-outer-longitudinal-tubular-structure end (40, 140), wherein the plurality of through channels (50, 150) are configured to receive at least one retaining structure, characterized in that the shelter (1, 2, 3) comprises the at least one retaining structure positioned inside a through channel of the plurality of through channels (50, 150) to provide reinforcement to the shelter and/or to anchor the shelter to the ground; wherein the first-outer-longitudinal-tubular structure end (30, 130) comprises a first-outer-longitudinal-tubular-structure end diameter, the second-outer-longitudinal-tubular-structure end (40, 140) comprises a second-outer-longitudinal-tubular-structure end diameter, and the first-outer-longitudinal-tubular-structure end diameter and the second-outer-longitudinal-tubular-structure end diameter are the same or the first-outer-longitudinal-tubular-structure end diameter is larger than the second-outer-longitudinal-tubular-structure end diameter, and/or, wherein the first-inner-longitudinal-tubular-structure-end (30, 130) comprises a first-inner-longitudinal-tubular-structure end diameter, the second-inner-longitudinal-tubular-structure (40, 140) end comprises a second-inner-longitudinal-tubular-structure end diameter, and the first-inner-longitudinal-tubular-structure end diameter and the second-inner-longitudinal-tubular-structure end diameter are the same or the first-inner-longitudinal-tubular-structure end diameter is larger than the second-inner-longitudinal-tubular-structure end diameter. an outer longitudinal tubular structure (4, 104) having an outer wall (10, 110), a first-outer-longitudinal-tubular-structure end (30, 130), and a second-outer-longitudinal-tubular-structure end (40, 140) diametrically opposed to the first-outer-longitudinal-tubular-structure end (30, 130); an inner longitudinal tubular structure (5, 105) positioned within the first longitudinal tubular structure (4, 104) and having an inner wall (20, 120), a first-inner-longitudinal-tubular-structure end (35, 135), and a second-inner-longitudinal-tubular-structure end (45, 145) diametrically opposed to the first inner-longitudinal-tubular-structure end (35, 135); and a segmented annular portion positioned between the outer wall (10, 110) and the inner wall, said segmented annular portion comprising a plurality of segmented annular divider walls defining a plurality of through channels (50, 150) extending from the first-outer-longitudinal-tubular-structure end (30, 130) to the second-outer-longitudinal-tubular-structure end (40, 140), wherein the plurality of through channels (50, 150) are configured to receive at least one retaining structure, characterized in that the shelter (1, 2, 3) comprises the at least one retaining structure positioned inside a through channel of the plurality of through channels (50, 150) to provide reinforcement to the shelter and/or to anchor the shelter to the ground; wherein the first-outer-longitudinal-tubular structure end (30, 130) comprises a first-outer-longitudinal-tubular-structure end diameter, the second-outer-longitudinal-tubular-structure end (40, 140) comprises a second-outer-longitudinal-tubular-structure end diameter, and the first-outer-longitudinal-tubular-structure end diameter and the second-outer-longitudinal-tubular-structure end diameter are the same or the first-outer-longitudinal-tubular-structure end diameter is larger than the second-outer-longitudinal-tubular-structure end diameter, and/or, wherein the first-inner-longitudinal-tubular-structure-end (30, 130) comprises a first-inner-longitudinal-tubular-structure end diameter, the second-inner-longitudinal-tubular-structure (40, 140) end comprises a second-inner-longitudinal-tubular-structure end diameter, and the first-inner-longitudinal-tubular-structure end diameter and the second-inner-longitudinal-tubular-structure end diameter are the same or the first-inner-longitudinal-tubular-structure end diameter is larger than the second-inner-longitudinal-tubular-structure end diameter.