We traveled in Spain last month; we had booked 2 Guided tours by Viator. The organisation of the tour and the quality of the guides were excellent in both cases. Entry to many important monuments in Spain is by tickets. These tickets are limited and on some days they are sold out even before the day begins. Even if daily tickets are available, the queues are long and time consuming. Through Viator bookings we completely avoided tension and made best use of our time. There were a couple of monuments in Barcelona where we had not anticipated this and wished we had booked in advance through Viator! We thought the Day trip from Granada to Cordoba was over-priced by Viator, and did the trip on our own -- it worked out cheaper. Although the website promised the trip at "upwards from $138", the "actual cost" worked out to more than $350. The original promise was misleading and the price difference between estimate and actual was too big to ignore. This was not value-for-money or clear communication --- principles which Viator is known for.