This culture also experimented with working with copper. Evidence of this, including stone anvils, copper knives, and a copper spearhead, was found on the Veluwe. Copper finds show that there was trade with other areas in Europe, as natural copper is not found in Dutch soil. The Bronze Age probably started somewhere around 2000 BC and lasted until around 800 BC. The earliest bronze tools have been found in the grave of a Bronze Age individual called "the smith of Wageningen". More Bronze Age objects from later periods have been found in Epe, Drouwen and elsewhere. Broken bronze objects found in Voorschoten were apparently destined for recycling. This indicates how valuable bronze was considered in the Bronze Age. Typical bronze objects from this period included knives, swords, axes, fibulae and bracelets. Most of the Bronze Age objects found in the Netherlands have been found in Drenthe. One item shows that trading networks during this period extended a far distance. Large bronze "situlae" (buckets) found in Drenthe were manufactured somewhere in eastern France or in Switzerland. They were used for mixing wine with water (a Roman/Greek custom). The many finds in Drenthe of rare and valuable objects, such as tin-bead necklaces, suggest that Drenthe was a trading centre in the Netherlands in the Bronze Age. The Bell Beaker cultures (2700–2100) locally developed into the Bronze Age Barbed-Wire Beaker culture (2100–1800). In the second millennium BC, the region was the boundary between the Atlantic and Nordic horizons and was split into a northern and a southern region, roughly divided by the course of the Rhine. In the north, the Elp culture (c. 1800 to 800 BC) was a Bronze Age archaeological culture having earthenware pottery of low quality known as ""Kümmerkeramik"" (or ""Grobkeramik"") as a marker. The initial phase was characterized by tumuli (1800–1200 BC) that were strongly tied to contemporary tumuli in northern Germany and Scandinavia, and were apparently related to the Tumulus culture (1600–1200 BC) in central Europe. This phase was followed by a subsequent change featuring Urnfield (cremation) burial customs (1200–800 BC). The southern region became dominated by the Hilversum culture (1800–800), which apparently inherited the cultural ties with Britain of the previous Barbed-Wire Beaker culture.