gliders, having large wingspan (typically 15' to 25') are designed to be easily disassembled for transport in trailers. The wings are generally two pieces (one per side) and fitted together in some interesting fashion inside the fuselage; a "Jesus Bolt" used to be common but is no longer favoured.
For example, a fork/tongue mechanism with a single vertical bolt holding them together:
front view:
---
-------------| |--++-------------
|J| ||
+---|e|--+|
|+--|s|---+
|| |u|
|+--|s|---+
+---| |--+|
|B| ||
-------------| |--++-------------
---
This method is no longer favoured due to the stress on the bolt applied over a short lever-arm (the height of the bolt). More recent aircraft use the whole width of the fuselage as the lever length and attach each wing to the other's root with pins:
top view:
wing jesus wing
root bolt root
|| -- ||
||---------------||--------------=||
|| || ==|
||---------------||--------------=||
|| || ||
||=--------------||---------------||
|==pin || ||
||=--------------||---------------||
|| -- ||
There is still a jesus bolt in the middle of the construction, but it takes no gravity/lift load. Its only purpose is to keep the wings together and attached, so takes only centrifugal and (to some extent) drag loads. With the wings both attached, the pins on each engage the sockets in the other's wing root. The lever length is the width of the aircraft, thus reducing stress.
Such a design does require heavier wing roots, to strongly couple the load from one wing's pin to the other's spar. The original jesus-bolt-under-load configuration had the bolt going directly through the spar.
Gliders have been known to fly without said bolt (in latter configuration), but discovery upon landings generally leads to shaky hands and red faces.
The jesus bolt holding the wings on/together is by no means the only. As mentioned above, there are other single points of failure holding on things like the tailplane, the loss of which would be catastrophic.