Sometimes travellers preferred the ford even where a bridge existed, as did one[104] at St. Jean de Maurienne on the post-route from France to Italy because the bridge was in such disrepair as to be unsafe. The same traveller crossed by boat at Otricoli beside the ruins of a Roman bridge which had once been a link in the Via Flaminia. On the bridges the same political reasons that kept the roads difficult had set their mark, accounting as they do for the number of wooden bridges, easier to dismantle in case of a raid. The bridges of Strassburg and Vienna were particularly striking examples of this; the planks were not even fastened down; if one end tipped up, a plank was as likely as not to fall into the river. Neither were there any rails at the sides. That was not exceptional, either, in spite of a bridge being worthy of remark if broad enough for two carts to pass each other. But whether it was the initial cheapness, or the habit of precaution, there they were, in spite of the cost of their upkeep, thirty thousand thalers yearly in the case of the one at Yarunov on the Vistula in the middle of the seventeenth century, when a thaler was nearly equal to one pound at present value. Yet the traveller[105] who reports this says his horse trod a hole in it. And in Hungary, when Busbecq returned from Turkey by road, the bridges offered so many traps for horses that robbers laid in wait under bridges for their best opportunities. As for stone bridges, Spain seems to have been the best off before 1600, but subsequently the improvement in bridges became very marked, especially in France. When Zinzerling knew Paris (1612-16), of its five bridges, only two were of stone, whereas of the six that Evelyn saw in 1643, but one was of wood. The only stone bridges in the empire that are mentioned are those of Schaffhausen, of Ratisbon, and, over the Moselle, of Coblentz; while two of the finest west of the Rhine, those of Avignon and Rouen, were impassable owing to gaps which no authority saw its way to repair. But the test of a first-rate bridge in 1600 was not how much traffic, but how many houses, it carried. Judged by this standard, it was agreed that London Bridge was the finest, with that of Nôtre Dame at Paris second, considering the latter's houses numbered sixty-eight. Still, it was with the number of bridges that the tourist was mainly concerned, in which matter he would find the Loire the only river across which passage was fairly easy; the Rhine had no bridge below Strassburg; the Seine had to be crossed five times by boat in the first four leagues of road northwards from Paris; and below Turin there existed no bridge over the Po except a wooden one at Ferrara.