"I only have 4 days in Italy, so I thought I would do a day in Venice, a day in Florence and 2 days in Rome, what do you think?"
I get this question, (or variations on it) regularly. I always ask, "why Italy?", and a recent response inspired today's post: "Well", the future traveler explained, "I know Italy has amazing museums, historic churches and squares, small atmospheric medieval streets, and a beautiful countryside with charming towns. And I love food and wine. Oh, and I'm learning some Italian so I thought I could practice."
Here's my advice: if you have limited time, pick a spot and see it properly. In Italy, you also want time to pay attention to detail, wander, and people-watch, maybe while sitting in a café in a piazza.
Stay in an agriturismo in Siena (like San Fabiano; or search for others on this website), and spend 2 days in the town itself plus 2 days exploring the Tuscan countryside.
Click on the link below to read about how to spend your 4 days.
Art & Architecture
The Campo: Start in Siena's main square, or Campo, home of the famous yearly Palio horse race. Sit in one of the cafés alongside the Campo and people-watch, admire the big fountain (an exact copy of) the Fonte Gaia with reliefs by Jacopo della Quercia (the original fountain is on display in Santa Maria della Scala). And notice the pavement design: very carefully considered, a shell-shaped space with nine spokes to represent the government, Il Nove (The Nine), who ruled at the height of Siena's glory.
Palazzo Pubblico: Climb up the 500 steps of the Mangia Tower (in photo, above) and enjoy the view over Siena, then visit the Palazzo Pubblico (also in photo above) and admire the famous political frescoes done by Martini and Lorenzetti in the Sala dei Nove. Martini's most famous fresco, Maesta', was completed before he relocated to Avignon, France to work in the Papal court. The Il Nove government then chose Lorenzetti to complete the room, and he did the Allegory of The Effects of Good Government and Bad Government. 
The Cathedral or Duomo: Start by stepping back to look at the façade. While my husband was taking the photo above, I was getting bored and decided to sketch the cathedral. Then a bride and groom emerged from the church, providing husband-photographer with a new subject, and giving me more time for my sketch. I probably spent at least 30 minutes trying to reproduce the cathedral on paper, and yet I was still surprised to find out that the lower part of the façade was done by Giovanni Pisano, and the upper part was done by someone else, at a later date.
But I digress.
Go inside to admire the incredible black and white striped design, Pisano's marble pulpit, and don't forget to look up: the ceilings are breathtaking. For a few weeks every year, its protected floors are uncovered for viewing: this year the floors can be seen from August 18th to October 30th.
The Piccolomini Library: Inside the duomo, this gorgeous space was financed by the nephew (and future pope Pope Pio III) of Pope Pio II to house his book collection, but was never actually used to store his books. It's famous for its ceiling and its frescoes by Pinturicchio and Rafaello, and you can see why from the photo, above.
Tavolette of Biccherna: Even the government's account books were decorated with incredible art: the 103 Tavolette of Biccherna, done by the most famous artists of the time, were covers for the governmental 13th- to 17th-century accounting books.
Baptistry: Next door to the cathedral, the baptistry houses Jacopo della Quercia's amazing baptisemal fountain.
Santa Maria della Scala: Named "della scala" because it's opposite the Cathedral's staircase, this is now a museum but started as a hospital for children, the poor, and pilgrims en route from Canturbury to Roma on the Via Francigena (which enters Siena via the Porta Camollia and exits via the Porta Romana). Worth a visit for both the architecture and art.
More worthwhile architecture: the Teatro dei Rozzi, a gorgeous working theater built in 1531 and damaged during WWII, was completely renovated in 1998. Admire the gorgeous architecture of the Palazzo Salimbeni. And visit the church of San Domenico, in the photo to the left.
Kids in Siena
Siena is a fabulous city for kids, because it is mostly traffic-free, small and walkable. It also works well for a treasure hunt: have the kids try to spot flags or fountains of the 17 contrade or neighborhoods. Each contrada has a fountain, stables, and a church - though they are not marked on maps so you'll just have to stumble upon them. For kids who are a little older, a unique activity is to sign up for a hot-air balloon ride: try www.flyballoon.it, www.chiantiballooning.com, www.balloonintuscany.com.
Markets
Every Wednesday from 8.30 - 12.30, the La Lizza market is open around the Fortezza. You can find clothing, scarves, bags, flowers, vegetables and fruit for reasonable prices. This is a huge market - probably 300+ vendors, and is geared more to the needs of locals than tourists.
There is an antiques market on the third Sunday of every month in Piazza del Mercato.
The Language
Italian as it is spoken on TV and taught in textbooks today originated from Dante, who was from this region. So if you want to emulate the "correct" Italian accent or learn Dante's Italian, Tuscany is the place to do it.
The Surrounding Countryside
Spend a day or two in Siena and the remaining couple days exploring the countryside. Do a wine tour, and consider visiting Monteriggioni, Montepulciano, Pienza, San Gimignano, and of course, Florence. Pick and choose - you can't actually do all of them in just 2 days. If you're there in the spring or early summer, you may even stumble upon a field of poppies or sunflowers.
Getting There
If you're getting to Siena from Florence, here's a good article on the best way to do it (in a nutshell: take the bus).
All photos in Siena except for San Domenico are by Sanjay
Photo of San Domenico by Mockney Piers