Abstract: Apparatus for constructing structures, particularly for children's playgrounds and gardens, includes a number of different types of elements, namely first elements in the form of logs having spaced parallel bores, second elements in the form of bars which are threaded at their ends and can be passed through the bores, third elements in the form of spacer tubes which pass over the bars and have an outer diameter greater than that of the bores, and fourth elements which can be screwed onto the ends of the bars and have an outer diameter greater than that of the bores. The logs, when in use, are positionable to various positions radially from the bars. The fourth elements engage the spacers and prevent the spacers and the logs from moving axially on the second elements or bars.