A piece of luggage comprising: a main body; an expandable body comprising a collapsible portion, the expandable body being connected to the main body through the collapsible portion; an expansion and locking device comprising a ratcheting assembly configured to allow free movement of the expandable body in a compression direction towards the main body and configured to enable locking of the expandable body in an expanding direction away from the main body; a cover pivotably connected to the expandable body; a zipper having a first half connected to the expandable body and a second half connected to the cover, wherein the first half and the second half are engageable to each other to close the cover with respect to the expandable body, such that a substantially enclosed space is defined by the main body, the expandable body and the cover; and a first pair of rotational wheels mounted to the main body and a second pair of rotational wheels mounted to the expandable body; wherein the main body comprises: a pair of bottom brackets, to which the first pair of rotational wheels are mounted, respectively; and the expandable body comprises a pair of bottom corner receivers, to which the second pair of rotational wheels are mounted, respectively; wherein the luggage stands on the first pair of rotational wheels and the second pair of rotational wheels, the first pair of rotational wheels and the second pair of rotational wheels are rotatable along a rotational axis that is substantially parallel to a rolling surface and along a spin axis that is substantially perpendicular to the rolling surface, wherein the first pair of rotational wheels each includes a plate adapted to conform to the shape of an external bottom surface of a respective bottom bracket, such that the first pair of rotational wheels can be snugly connected to the bottom brackets, respectively, and wherein the second pair of rotational wheels each includes an L-shaped plate adapted to conform to the shape of an external bottom surface of a respective bottom corner receiver, such that the second pair of rotational wheels can be snugly connected to the bottom corner receiver, respectively. a main body; an expandable body comprising a collapsible portion, the expandable body being connected to the main body through the collapsible portion; an expansion and locking device comprising a ratcheting assembly configured to allow free movement of the expandable body in a compression direction towards the main body and configured to enable locking of the expandable body in an expanding direction away from the main body; a cover pivotably connected to the expandable body; a zipper having a first half connected to the expandable body and a second half connected to the cover, wherein the first half and the second half are engageable to each other to close the cover with respect to the expandable body, such that a substantially enclosed space is defined by the main body, the expandable body and the cover; and a first pair of rotational wheels mounted to the main body and a second pair of rotational wheels mounted to the expandable body; wherein the main body comprises: a pair of bottom brackets, to which the first pair of rotational wheels are mounted, respectively; and the expandable body comprises a pair of bottom corner receivers, to which the second pair of rotational wheels are mounted, respectively; wherein the luggage stands on the first pair of rotational wheels and the second pair of rotational wheels, the first pair of rotational wheels and the second pair of rotational wheels are rotatable along a rotational axis that is substantially parallel to a rolling surface and along a spin axis that is substantially perpendicular to the rolling surface, wherein the first pair of rotational wheels each includes a plate adapted to conform to the shape of an external bottom surface of a respective bottom bracket, such that the first pair of rotational wheels can be snugly connected to the bottom brackets, respectively, and wherein the second pair of rotational wheels each includes an L-shaped plate adapted to conform to the shape of an external bottom surface of a respective bottom corner receiver, such that the second pair of rotational wheels can be snugly connected to the bottom corner receiver, respectively. wherein the first pair of rotational wheels each includes a plate adapted to conform to the shape of an external bottom surface of a respective bottom bracket, such that the first pair of rotational wheels can be snugly connected to the bottom brackets, respectively, and wherein the second pair of rotational wheels each includes an L-shaped plate adapted to conform to the shape of an external bottom surface of a respective bottom corner receiver, such that the second pair of rotational wheels can be snugly connected to the bottom corner receiver, respectively.