Taxis can only be hailed at strategically located stands or by telephone. Avoid taxis that are not metered. Whenever possible, I avoid taking a taxi and rely on the bus, underground, or trams. Run by many travel agencies, these tours allow first-time visitors to get a general impression of the main sights and enables them to plan further sightseeing. Information is available from the local tourist office.
Horse carriages are available in Rome.
Charges are high. Check with local information offices for the best tour for you. I always research the destinations to which I intend to travel with books and maps. I normally use Fodor's as I find their guidebooks very informative and easy to read and understand. Click on the Amazon logo to search for travel books and maps.