#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll a[65];
ll num[100005];
ll x;
int main() {
        int TNT;
        scanf("%d", &TNT);
        while (TNT--) {
                memset(a, 0, sizeof(a));
                int n;
                ll sum = 0;
                scanf("%d", &n);
                for (int i = 1; i <= n; i++) {
                        scanf("%lld", &x);
                        num[i] = x;
                        sum ^= x;
                }
                for (int i = 1; i <= n; i++) {
                        num[i] &= sum;
                }
                for (int i = 1; i <= n; i++) {
                        for (int j = 62; j >= 0; j--) {
                                if (num[i] & (1ll << j)) {
                                        if (!a[j]) {
                                                a[j] = num[i];
                                                break;
                                        } else {
                                                num[i] ^= a[j];
                                        }
                                }
                        }
                }
                int aim = -1;
                ll aimx = 0;
                for (int i = 62; i >= 0; i--) {
                        if (sum & (1ll << i)) {
                                aim = i;
                                aimx = a[i];
                                break;
                        }
                }
                for (int i = aim - 1; i >= 0; i--) {
                        if (aimx & (1ll << i)) {
                                aimx ^= a[i];
                        }
                }
                ll ans = aimx - (aimx ^ sum);
                printf("%lld\n", ans);
        }
}